Making money from the rain
I have just won £10 in the Walker's Crisps Rainy Day promotion. Each packet of crisps has a code that allows you to choose a 2km x 2km square in the UK or Republic of Ireland in which you think it will rain in a couple of days time. I won after only three entries at a crisp cost of £1.20, which seems quite a good deal.
By 8am on 22nd October there had been 314,000 entries and 36,000 winners, that's a payout rate of 11% (these numbers can be found here). At 40p a packet these are fine odds (although be aware that 18-pack multi-bags only contain 3 plays).
You are only allowed one entry a day, and the strategy choices are interesting. Up to 8am on day X you can 'bet' on day X+1, which allows the use of a better weather forecast but by then most of the squares have gone. After 8am on day X you place bets on day X+2 and so the forecast is more distant, but there are more choices.
Each day the squares chosen by competitors are initially concentrated on cities rather than where it rains on the wet and green areas of Scotland, Wales and Ireland. This suggests that people are choosing squares near where they live rather than checking the weather forecast. Since this promotion is done in collaboration with the Met Office, this is not very encouraging. I believe that checking the forecasts improves the odds over the 11% average - however my 1 out of 3 success rate is hardly enough data to claim great skill.
Roll on a nice rainy November!
Added 7pm 22nd October: Just won again. Clearly the way to beat the cuts.