Oz Weather Apponomics – Birthday Edition

This is the latest installment tracking the progress of the Oz Weather iPhone app in the iTunes app store. (Part 7 installment here.)

Oz Weather v1.0 arrived in the app store on 1st November 2008 (now at v1.7.1), so I now have a full years of stats to share with you.

  • Total paid app downloads: 64,500 (176 per day on average)
  • Net app revenue: AUD$99,600 (US$89,700) – net of 30% Apple share and 10% Australian GST
  • Average User Rating: 4 stars – from 1187 ratings of all versions
  • Average ranking: 17.5 – in Australian app store

[Stop Press – AUD$100k sales were reached on 3rd Nov 2009]

The following graph shows a complete history of one year’s worth of daily sales records.


The associated Australian overall paid apps ranking is as follows:


So there have been a number of peaks and troughs. The single biggest factor causing those peaks and troughs appears to have been Apple promotions in the Hot / New / Staff Pick lists. But this has worked both ways – the biggest troughs have occurred when Apple has promoted competing apps.

The second biggest factor has been the weather itself. In Australia it seems that people are more interested in summer weather than they are in winter weather, hence causing an underlying annual cycle which peaks in summer (Dec/Jan/Feb) and troughs in winter (Jun/Jul/Aug).

Some individual weather events (eg. extreme heat waves, major rainfall events) seem to account for much shorter term peaks – especially noticeable around Feb 2009 when a major app update was also released.

Its also worth noting that during the course of the year the number of competitors has grown substantially. No doubt other developers have noticed how well weather apps seem to do in the app store ecosystem, and I would guess that my blogging about such attractive sales figures has probably encouraged some of the new ones into the game too. 😉  However, most of the newer competitors have failed to get any significant visibility, at least so far, and overall I don’t regret my decision to be transparent and open with my sales figures. I am always delighted to read about the inside stories of other app developers’ successes and failures, and hope that my own story has been interesting and useful to others too.


Estimated Total Value of App Store Market

AdMob has just issued a report with some very interesting data on the app store, and one of their claims is that the app store market is worth about US$200M per month.

This is disputed as being an unreasonably high estimate by some commentators. However, with data I have gathered from my own app sales, I am in a position to make my own estimate too. So what is it? Well there are four steps.

Step 1 – Sales Versus Rankings

In an earlier post I showed a graph of sales versus rankings for Oz Weather in the Australian app store during the first few months of 2009. Below is an updated graph covering the sales period July/August 2009.

Oz Weather Paid Rankings

Although Oz Weather hasn’t ranked highly enough to provide data points within the top 10, it does still allow a good estimate of the curve as a whole ie.

Daily Sales = 1800 * Ranking ^ -0.8

Note that this curve is substantially higher than the 6 month-old estimate, showing a large increase in the overall number of app sales per day – of the order of a factor of  2 or more.

Step 2 – Find area under the curve to give total daily app sales

The area under this curve is the integral of the curve formula. With some high-school calculus, we might know that this is:

Area under curve = 1800 * (Ranking^0.2 / 0.2)

Solving this for the range 0 to 50,000 apps (the approximate number of paid apps available) gives the result:

52,000 app sales per day in the Australian app store

Step 3 – Multiply by average app price

Assuming an average app price of US$1.80 (AUD$2.25) the total daily revenue for the Australian app store alone is

  • AUD$120k per day
  • AUD$3.6M per month
  • AUD $42.7M per year

Step 4 – Expand to whole Globe

I have previously estimated the Australian market to be about 1/30th of the global market size. However, the AdMob report indicates about 45M iPhone/iPod Touch devices worldwide, and previous research has implied about 1.1 million in Australia, implying a ratio of about 1/40. In that case, the corresponding global sales figures would be

  • US$3.9M per day
  • US$115M per month
  • US$1,370M per year


Although there are a number of estimates and assumptions involved in these calculations, the final monthly number of US$115M per month, although less than AdMob’s estimate, only differs by a factor of a 0.6.

A more accurate estimate would be possible with a wider range of app versus ranking data – especially from the larger app stores like the US. However, I did previously collate some data like this, and it also supported a rankings/sales tail off with a power factor close to -0.8.

I conclude that my own app’s sales figures imply that AdMob’s estimates are very plausible, and certainly likely to be in the correct ballpark.

Oz Weather Apponomics – Part 7

This is the latest installment tracking the progress of the Oz Weather iPhone app in the iTunes app store. (Part 6 installment here.)

The latest stats, to 4th August 2009:

* Total app downloads: 48,600
* Net app revenue: AUD$73,800 (US$59,000) – net of 30% Apple share and 10% Australian GST
* Average User Rating: 4 stars – from 885 ratings of all versions

The following graph shows a complete history of more than 8 months of daily sales records, since launch on Nov 1st 2008.


The associated Australian overall paid apps ranking is as follows:


I already explained the cause of the great sales dip in June in the previous post, but the other feature that stands out here is how the ranking in the latter half of the graph has been declining despite a fairly constant average base level of sales (excepting June). The obvious explanation for this divergence is that the total number of all apps being bought is gradually increasing with time as the number of iPhones/iPods in Australia has increased. Recent estimates by AdMob put the total number of iPhones in Australia at around 750,000 and iPod Touch at 350,000 – making a combined total of 1.1 million devices on which Oz Weather could be installed. This would mean that Oz Weather has been purchased by about 4.4% of Australian device owners.

This might seem to leave room for plenty more sales, but others have suggested that 3% is a high ownership rate for other popular apps such as “Flight Control”, so maybe we’re already pushing the boundaries!

Oz Weather Apponomics – Part 6

This is the latest installment tracking the progress of the Oz Weather iPhone app in the iTunes app store. (Part 5 installment here.)

The latest stats, to 3rd July 2009:

* Total app downloads: 44,800
* Net app revenue: AUD$68,000 (US$54,400) – net of 30% Apple share and 10% Australian GST
* Average User Rating: 4.5 stars – from 6 ratings of latest version, 4 stars – from 790 ratings of all versions

The following graph shows a complete history of more than 7 months of daily sales records, since launch on Nov 1st 2008.


The associated Australian overall paid apps ranking is as follows:


The most immediately noticeable feature of these graphs is the big “crash” in sales and rankings starting at the beginning of June, and then the sudden recovery on 26th June. What could have caused these big changes in fortune?

  • The Fall – At the beginning of June, Oz Weather’s main head-to-head competitor (Pocket Weather AU) was given “Staff Favourite” status in the Australian app store, which meant that it appeared on the front page of the app store with that endorsement. So at the same time that Oz Weather sales and rankings tanked, Pocket Weather sales and rankings  took off. While Oz Weather reached its nadir at 68th ranking, Pocket Weather peaked at around 29th ranking.
  • The Recovery – On 26th June, Apple launched the iPhone 3GS in Australia. Oz Weather sales tripled overnight and its ranking jumped from 60th to 20th, while Pocket Weather’s ranking remained much steadier, hovering around the 40th to 50th ranking range. My surmise as to what caused this is Apple’s in-shop promotions which include Oz Weather as one of the featured apps, and a demo version is pre-installed on some of their iPhone shop demo units. This means that new iPhone customers who visit an Apple store to make their purchase get well exposed to Oz Weather.

Interestingly, the cause of both the fall and the recovery are apparently Apple’s own promotional mechanisms, over which individual developers have (as far as I am aware) absolutely no control. Either you are picked or you are not!

Overall, of course, Apple’s influence has been much more of a benefit than a hindrance to Oz Weather, and I am of course very grateful for that. And I certainly do not begrudge the fact the Pocket Weather was given a staff favourite pick by Apple. Like me, they’ve put a lot of time and effort into their app, and deserve their day in the sun as much as anyone else.

Oz Weather Apponomics – Part 5

This is the latest installment tracking the progress of the Oz Weather iPhone app in the iTunes app store. (Part 4 installment here.)

The latest stats:

  • Total app downloads: 40,000
  • Net app revenue: AUD$60,800 (US$46,800) – net of 30% Apple share and 10% Australian GST
  • Average User Rating: 4.5 stars – from 105 ratings of latest version

The following graph shows a complete history of more than 6 months of daily sales records, since launch on Nov 1st 2008.

Oz Weather Sales to Date

It is apparent that, although sales have declined quite a lot from their peak in early Feb 2008, they now appear to have leveled out over the past two months at an average of around 125 sales per day.

The app ranking (amongst all paid apps in the Australian iTunes store), however, is a little more volatile.

Oz Weather Ranking

If you look at the long term trend this might be interpreted as showing a ongoing decline. However, if just the last two months are taken in isolation, then it is also possible to interpret it as having leveled off at around the #20 ranking mark, albeit with greater volatility – and this seems to be given some support from the actual sales numbers. In fact greater volatility is always to be expected at a lower ranking, due to a crowding of other apps with similar sales levels, such that only small variations in sales numbers can make much larger changes to their relative rankings.

Apple Promotions

Also of significant interest may be the fact that Apple has actively included Oz Weather in their advertising and promotions. These have included:

  • Icon and app description featured in the Sydney Apple Store on mural advertising display
  • Icon and app description featured in the Sydney Apple Store in “Lifestyle” app plaques placed around iPhone/iPod sales areas
  • Demo version of app is included on some demo iPhone/iPod devices in the Sydney Apple Store
  • Icon and app description featured in full page national and local newspapers (Australian, Financial Review, Sydney Morning Herald, The Age)
  • Icon appears in some of Apple’s iPhone television advertisements

Oz Weather - Apple Store Mural

Some of these promotions have been ongoing for a couple of months (Apple Store), and others are more sporadic (TV and newspapers ads). However, I have been unable to spot any significant correlation between the timing of these promotions and changes to app sales figures. Given that sales levels appear to have stabilised, if there is any effect from these promotions, it suggests that the effect may been to prevent a further falloff in sales, rather than actually increasing them.

Of course there is still the possibility of a seasonal effect that I referred to in an earlier post, and perhaps when more severe winter weather sets in sales levels could increase again. In fact the sales of other weather apps appear to have suffered a similar decline in rankings to Oz Weather,which would be in line with this hypothesis, but on the other hand it may also simply be reflecting the huge increase in the number of apps available (four times more than when Oz Weather launched), or even a market saturation of weather apps. If estimates of the number of iPhones in Australia are accurate, then Oz Weather is already installed on 10% of them. It might be hard to get a better market penetration than that, for a paid app!

As usual, I’ll report back again with further information when time permits.

Oz Weather Apponomics – Part 4

This post provides an update to the progress of Oz Weather in the Australian app store.

First, here are some of the most recent milestones, highlights and points of interest.

  • Total app downloads: 34,800
  • Net app revenue: AUD$52,500 (US$37,000)
  • Highest paid app ranking: #1 (for 12 consecutive days)
  • Lowest paid app ranking: #17 (excluding app store technical glitch)
  • Average paid app ranking: #6 (over app lifetime)
  • Upgrade uptake half-life: 5 days (average time for 50% of existing users to update to new versions)
  • Total weather queries served: 3.8 million
  • Split between iPhone / iPod Touch user base: 89% / 11%

And here is the complete history of daily sales to date (ie. from 1st November 2008 to end of first week of April 2009).

Oz Weather Sales

I have listed some probable causes for some of the ups and downs in my previous posts, but the newest “feature” here is what looks like a downward trend since the peaks of early February, although the last 20 days or so could be showing a leveling off – perhaps to some kind of base sales level around 100 to 150 sales per day. This is lower than the figure of 150 to 200 I had suggested in an earlier post, but the correlation between daily sales and weather queries per day seems to have become even clearer, as evidenced by the following updated graph.

Weather vs Sales

If you compare this graph with the earlier version from a month ago, you will see that the more recent, lower level of daily sales on the leftmost part of the graph correlate well with decreased level of app usage by existing customers – which was down to about 0.75 queries per day per app in some cases.

This suggests two possibilities to me

  • Long term users may be experiencing app fatigue, overload or dilution, and are no longer using older apps as much as they used to.
  • During this inter-seasonal period with less weather extremes, the weather is of less interest to people in general, and hence existing app owners use the app less, and new iPhone owners are less likely to want to buy a copy.

It is worth noting that sales of other Australian weather apps appear to have experienced broadly similar trends to those of Oz Weather, as evidenced by their rankings which have broadly followed the movements of Oz Weather’s own rankings. Therefore it seems that competitive factors are not a significant factor here.

Based on the evidence to hand, I suspect that the issue of less interesting weather is the most significant one. If this is indeed so, then sales can be expected to increase again when bouts of extreme winter weather start to hit Australia.

So that is my hypothesis, and I will report back later with further data which may support or refute it.

Estimating App Sales From Rankings – Part 2

In an earlier post I showed a graph of Oz Weather’s daily sales levels versus its ranking in the Australian iTunes app store, and then extrapolated the findings to get a very rough estimate of global sales versus iTunes US app store rankings.

Australian Sales vs Rankings

As Oz Weather has now been selling for more than 3 months, and has had an extended period ranked #1 in the Australian store, so I am now in a position to make an enhanced analysis. But note that there were some anomalous sales figures over the Christmas period (24th Dec to 31st Dec) due to three unusual circumstances:-

  • the surge in overall Christmas sales
  • the fact that I discounted the app over that period
  • thirdly due to a major loss of sales when the app store broke down temporarily

The graph below shows the entire history of sales, minus that week’s worth of  “anomalous” sales data.

Sales Rankings Australia

I tried fitting logarithmic, exponential and power curves to the data – the power curve gave by far the best fit, with the approximate equation

Daily Sales = 425 * Ranking ^ -0.5

This equation can be used to give a reasonable estimate of sales of paid apps in the Australian iTunes app store using the overall ranking (not the ranking in any individual category such as entertainment, lifestyle, weather etc). However note that there is a wide range of variation about this mean trend line on a day to day basis. For example while Oz Weather was ranked #1 sales varied between about 260 and 620, and at rank #2 from 190 to 420.

World Sales versus Rankings

We now have a good idea of the apponomics of the Australian store, but what about world-wide sales? To begin to answer this, I have gathered as much data as I could find  giving US store app ranking versus daily sales. The main sources I found were

Using data from these sources – some real sales figures and others inferred and estimated, I constructed the following graph. 

Sales Ranking World

The main assumption here is that US rankings reflect Worldwide rankings reasonably well, which although not necessarily true for specific apps, is probably true on average. Also note that, to clarify the picture, I did exclude some of the higher figures given for #1 ranking – up to 50,000 or more supposedly. I suspect that sales at the #1 spot will be much more variable than lower ranked slots, so it seemed sensible to include only the lowest figures that resulted in a #1 ranking, for this purpose.

As before I tried fitting logarithmic, exponential and power curves to the data – and again the power curve gave by far the best fit, with the approximate equation

Daily Sales = 15000 * Ranking ^ -0.75

This equation can probably be used to give a reasonable estimate of sales of paid apps in the US iTunes app store using the overall ranking. It roughly confirms my earlier guess that world sales were typically 30 times more than Australian sales. In fact, for the given equations, the World/Australia sales ratio varies from 35 (#1 ranking) to 13 (#50 ranking).

Given that there is no reason to suspect any major difference in sales dynamics, one might have expected the ratio to remain similar at all rankings (ie. the power factor to be the same in each equation). However, note that the Australian curve is based on data only going down to #17 ranking, whereas the US curve has data down to #100 ranking. I therefore suspect that the US curve power factor is more realistic for the long tail, and that the drop-off in sales levels for Australia well below the #20 ranking might be somewhat less than that predicted by the given equation.

So there you have it – the best that I can do with the available data. As more data becomes available I will add it in to the mix, to see how much further this can be refined.

Oz Weather Apponomics – Part 3

Following on from Apponomics Part 1 after the first two weeks of sales and Apponomics Part 2 after one month of sales,  Oz Weather has now had just over three full months of sales. Here is a complete history of the daily unit sales numbers, up until 5th Feb 2009.

Sales to 5th Feb 2009

The red and yellow bars show Australian and overseas daily unit sales at AUD$2.49 (US$1.99), and the blue and orange bars are at the temporary sale price of AUD$1.19 (US$0.99).

I’ve annotated the graph with some significant events which did (or might have been expected to) affect sales volumes. These events were as follows.

  • Release of v1.1 Update – saw an immediate jump in sales and rise in ranking from #6 to #3
  • Release of v1.2 Update – sales flat
  • Xmas Sale – decided to try a brief sale over Christmas period due to falling sales & ranking having dropped to #9
  • App Store Broken – a couple of days when customers were unable to purchase Oz Weather
  • Major Heatwave in Parts of Australia – consistently high sales level, bringing ranking to #2
  • Release of v1.3 Update – major app enhancements and an eye-catching new icon pushed the Australian iTunes paid app ranking to #1 – where it remains at time of writing

Summary of Sales & Revenue

  • Total units sold: 23,800
  • Average sales per day: 245
  • Approximate revenue: AUD$35,000 (US$22,500)

Upgrade Statistics

  • Total units sold prior to v1.3: 19,800
  • Total upgrades to v1.3 in 9 days since release: 13,350
  • Upgrade ratio: 67.4%


Although I indicated in a previous blog entry that I had broken even on 19th December, I did invest considerable extra development time and effort into the latest app update, and also into further professional design work . Consequently I estimate my total nominal costs so far to be around the AUD$25,000 (US$16,000) mark. This leaves a nominal profit to date of AUD$10,000 (US$6,400).

Thoughts and Comments

Although Oz Weather has been substantially profitable (for a sole developer) over this 3 month period, the apponomics depend to a large degree on how much ongoing additional development effort is required to maintain its level of sales. So far, Oz Weather sales levels have not dropped off in a way that seems to be typical of many other apps. It remains an open question as to how much of this is due to the additional development effort I have made versus what would have happened without this frequency and depth of app updates.

Competition is of course another important factor. Whilst Oz Weather has taken the major share of the Australian Weather apps market since its launch, the visibility of its success is an encouragement to competitors. The developers of Pocket Weather have made no secret of the fact that they would very much like to regain the position they had in the app store before Oz Weather jumped in, and appear to be investing considerable time and effort into fighting back with their own major updates. There also remains the possiblity if not likelihood that some other major player in the Australian weather scene will want to launch their own app, backed with pre-existing infrastructure which will give them some competitive advantages.

So despite all the stories you might hear about overnight successes in the app store, overnight falls from grace are probably just as frequent. In reality, it is just a reflection of life as a whole. Hard work and listening carefully to your users will maximize your chances, but the only real certainty is uncertainty! Stay tuned for the next instalment.

Oz Weather a Hit in Pakistan?!

For your enjoyment, here is a recent Twitter thread I participated in.

Tim Haines tweets are in this color. My tweets are in this color. 

  • @gpdawson Did you know that Oz Weather was in the top paid list for Pakistan 3 days ago? At number 77 no less. Did their cricket team visit?
  • @timhaines What a gem! I’ll have to add that into my promo. No Pakistan cricket team here. But I’m guessing not many sales for #77 in P. 
  • @gpdawson It was 3 days ago, do you have sales stats for then? I’d be interested in how many sales were needed? Maybe 2? 🙂
  • @timhaines In past two weekly reports there was 1 (one) sale in Pakistan. And 0 (zero) in latest daily reports. LOL!!!
  • @gpdawson Ha. Apparently by having 1 sales, you can get to number 77 on Pakistan’s top paid list. Woot! @gpdawson did it with Oz Weather

So yes, apparently just one sale makes it to #77 in the Pakistan iTunes store. 

In fact it seems similar is true of a number of national iTunes stores. @veiledgames reported that just one sale in Israel puts them in the top 50 there. And @majicDave reported that four sales was enough to get to #1 in Lebanon.

Let’s just say there is obviously a lot of potential for growth in these places. 🙂  Maybe the much anticipated (but as yet purely speculative) Nano iPhone or iPod Touch will help things along.

Oz Weather Xmas Sales – Is the App Store Broken?

You may already have heard from some other sources that iPhone app sales were very strong over the Christmas period, possibly enhanced by many new iPod Touch devices being delivered from Santa’s sleigh.

I can certainly confirm that it was a strong sales period for Oz Weather – although the picture is complicated by the fact that I temporarily dropped the price for the Christmas period. Here are the daily sales figures to date – from 1st November to 29th December.


The red and yellow colors show units sold at the normal price of AUD$2.49 (US$1.99). The purple and orange colors show units sold at the discounted price of AUD$1.19 (US$0.99) – a sale which started on 24th December (day 54) and finished on 28th December (day 58).

Key Points

  • The break-even point for the Oz Weather project was reached on 19th December (day 49) – ie. cumulative net revenue of AUD$15,500 (US$10,850).
  • After ranking as high as #2 in Paid Apps category of the Australian app store from 5th to 9th December, ranking fell gradually to #9 on 23rd December. Hence my decision to run a price sale over the Christmas period.
  • Christmas Day had the highest ever sales of 451 units – followed by similar levels on 26th and 27th December. The app ranking rose to #2 again. This is the celebratory part of this article. 🙂
  • The last item on the graph (item 59 = 29th December) shows daily sales of just 17 units. This is not an error, and not just a partial day’s sales. It was the actual full day’s sales! Ranking has fallen to less than #10 – but to exactly what level is not possible to ascertain, due to problems in the app store. This is the disappointing part of this article. 😦

Major App Store Technical Problems

Did people suddenly stop wanting to buy Oz Weather because the price discount had ended? Did Oz Weather suddenly become unpopular? Did a competitor suddenly release a much better app?

The answer to all these question is no. Many people are still wanting to buy Oz Weather, but are unable to do so, due to problems in the app store. On the 29th and 30th December I received 7 emails from potential customers wanting to know why they couldn’t purchase it. This is very likely the tip of the iceberg. The vast majority of customers simply wouldn’t bother trying to contact the app publisher when they receive a message like the following (sent to me by a customer).


So what is going on here, Apple? I have tried contacting Apple support, and so far have only managed to get an automated reply saying:

Please plan for a delayed response time from the iTunes Connect Support team from December 23rd through January 5th as we will be short-staffed over the holiday break.

It is apparent that the app store problems go beyond just the Oz Weather app. The Australian store paid app rankings were “stuck” for several days, and showed widely different results depending on exactly where you look at the rankings.

  • iTunes home page – showed Oz Weather #6 – this morning dropped off the table
  • iTunes app store main page – showed Oz Weather #4 – this morning dropped off the table
  • iTunes top 100 paid app rankings – showed Oz Weather #2 this morning – this afternoon had dropped to #23
  • iPhone top 25 rankings – showed Oz Weather #6 – still now at #6

I am not generally one to jump on the hindsight bandwagon – but in this case I am very tempted to say to Apple that “you should have realised that Christmas was going to be your busiest period, and employed extra staff instead of sending them all on vacation”. Now I am in a position where, due to this Apple glitch, I am probably losing several hundred dollars per day in sales, and my app ranking has artificially fallen from #2 to way off the radar – and I can’t find any way to get any response from Apple.

My questions to other app developers

  • Am I the only one having such serious app store problems?
  • If not, then do these problems affect only apps which are undergoing price changes?
  • Do these problems affect only the Australian app store?
In the absence of any way to get immediate support from Apple, I’m really hoping that someone who reads this blog can provide some useful feedback!

Late Addition (31 Dec): The following link to a PCWorld article which indicates that there have also been other app store/iTunes problems this Xmas.

Late Addition (1 Jan): I am not alone. The app store IS broken. See the comment from VPool.