Monday, July 27, 2009

Nate's Silver's wager

Noting observations by some in the blogosphere that this seems to be an unusually cool summer, Nate Silver has offered the following bet to climate change skeptics:
The rules of the challenge are as follows:

1. For each day that the high temperature in your hometown is at least 1 degree Fahrenheit above average, as listed by Weather Underground, you owe me $25. For each day that it is at least 1 degree Fahrenheit below average, I owe you $25.

2. The challenge proceeds in monthly intervals, with the first month being August. At the end of each month, we'll tally up the winning and losing days and the loser writes the winner a check for the balance.

3. The challenge automatically rolls over to the next month until/unless: (i) one party informs the other by the 20th of the previous month that he would like to discontinue the challenge (that is, if you want to discontinue the challenge for September, you'd have to tell me this by August 20th), or (ii) the losing party has failed to pay the winning party in a timely fashion, in which case the challenge may be canceled at the sole discretion of the winning party.
If you're out to make a point about climate change it's a pretty silly wager. Climate change takes place over many years, not months, and the bet -- unlike the 10 year Simon-Ehrlich wager -- is rather meaningless. Nevertheless I've been tempted because it has felt to me that the DC area has been experiencing a rather cool summer and I could use the extra cash. Unfortunately the terms of the bet prohibit me from participating because my blog traffic does not rank in the top 50,000.

Out of curiosity, however, I decided to crunch the numbers and see where the bet would stand if Nate Silver and I had placed such a wager on Jan. 1 of this year. I went to Weather Underground and got all of the 2009 weather data for Washington DC and matched it against the historical averages from

What I found was that the number of days where the recorded high was at least one degree warmer than the historical average was 54. The number of days where the recorded high was at least one degree cooler, however, was 123, with a further 20 days where the recorded high was within one degree of the average high. The numbers don't add up to the number of days that have transpired so far this year because for about 7 days there was no data, including several bitterly cold days in late January (I remember because the dates include Obama's inauguration, where my toes hurt they were so cold).

Thus, if the bet had been placed Silver would owe me $1,725 -- (123 minus 54) multiplied by $25.

I'll be glad to provide a copy of the Excel spreadsheet to whoever emails me (2getrichisglorious - at -

1 comment:

Josh said...

I don't know who Nate Silver is, but his proposed wager shows absolute ignorance of climate change. Shocking, another global warming backer who has no clue about science.