Some time ago, Tom Adams (CTO, MoGeneration) asked me whether there was any link between Oz Weather sales and the unusually stormy weather we’d been having in Queensland. And at that time I couldn’t think of any obvious way to find out.
However, a few days ago inspiration finally struck. It occurred to me that one of the server stats I’d been recording was producing a pretty good indication of how unusual or interesting the weather was on any given day. That statistic is the number of weather queries per installed app.
Typically this seems to be 1.0 to 1.5 weather queries per day per app, but this peaked at about 4.3 weather queries per app during the recent Victorian extreme heatwave and bushfires. In fact there were more than 100,000 queries on that day alone, from an installed base of about 24,000 units. So the next step was to visualise the data graphically to see if there was any relationship in general over time, as shown below.
There does indeed appear to be a relationship here! The blue curve is a logarithmic best fit, although a linear fit would probably have been as good.
The conclusion I am drawing from this is that there is “base” level of sales of around 150 to 200 per day, and that rate increases by 100 or more sales per day as the weather becomes more extreme, interesting or newsworthy.
You might question whether I’ve got the relationship the wrong way around here ie. whether in fact the new daily sales are causing the higher query rate than usual as people first tried out the app. No doubt this is indeed a factor. However, given that new daily sales are typically only about 1% of total apps already in use, it seems very unlikely that this could actually account for the large changes observed.
In terms of app rankings, it interesting to note that Oz Weather finally jumped into #1 position in the paid app rankings on a day when there were 4.1 weather queries per app. It remained there for 12 days, while the rate of weather queries averaged 2.5 per app (ranging from 1.5 to 4.3). It finally fell back to #2 position again on the day that the weather query rate had dropped back to 1.3 per app, and since then it has dropped further to #6 position, with an average weather query rate of just 1.2 queries per app over the last 20 days.