Wow, it really has been a chilly summer

Yesterday, I looked at Nate Silver's weather challenge where he would bet prominent bloggers that it wasn't really as cold as they thought it was. Essentially he would have paid $25 for every day two or more degrees below average and the opponent would have to pay Nate $25 for every day where it was two or more degrees warmer than normal. I wrote yesterday that I thought his logic was flawed because he was using actual temperature data from one station to and comparing it to daily averages from another, making it look like it was really warmer in the test city (Minneapolis) than it actually was.

Well, I thought I might take a look to see how this would have worked if I were eligible for the bet and I used the closest weather station (ORH in Worcester) as my basis for actuals and averages.

From June 21 through July 18, the high temperature in Worcester has exceeded the average only twice times--once by two degrees, once by one degree. The actual high has equaled the average high just once. On the other 25 days, the high temperature in Worcester has been lower than the average, and only twice has it been within one degree. So if I were able to make the bet (and the offer had come in June), I would be ahead of Nate by a whopping $550.

If I use my criteria of meteorological summer, Nate would have to pay me out another 8 days (13 additional days two or more degrees below average, as opposed to five days two or more degrees above) putting me up by $750.

(It's amazing to think that the high temp here has been below average on 40 of the last 49 days. The temperature did not even reach 80 degrees between May 22 and July 17. The highest temperature recorded in 2009 was on April 28.)

I knew it had been cool, but I didn't realize it had been that cool.

Tags: Climate Change fivethirtyeight Nate Silver Massachusetts Worcester

Nate Silver's Weather Whoopsie

Nate Silver runs the fivethirtyeight.com web site, which provides incredibly interesting and valuable coverage of politics, especially election politics. His statistical models predicting the presidential and senatorial elections were incredibly accurate. Since the election, he has been using statistics to look at policy issues as well as political horse races. It's one of the handful of blogs that I read everyday.

In that vein, he posted a piece Saturday challenging climate change skeptics to a bet. He argues that while it seems like it is a little cooler this summer than normal, it actually is not. He used the example of the Minneapolis-based Powerline blog--which had recently posted an article comparing this summer to a "year without a summer" as the basis for his challenge:

Indeed, it's been pretty cool in Minneapolis for the past couple of days; the temperature hasn't hit 70 since midday Thursday. But has it been an unusually cool summer? No, not really. Since summer began on June 21st, high temperatures there have been above average 15 times and below average 13 times. The average high temperature there since summer began this year has been 82.4 degrees. The average historic high temperature over the same period is ... 82.4 degrees. It's been a completely typical summer in Minneapolis, although with one rather hot period in late June and one rather cool one now. (Note: actual high temperatures can be found here and historical averages can be found here.)

After setting up the premise, he issued the challenge:

• 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.

Sounds like a cool idea. Since next to no one reads my blog I'm not eligible for the bet, but I figured I could at least play along for pretend money. Mind you, I am not a all a climate change skeptic--I'm sure that the earth is gradually warming and it would behoove us to do something about it--but it still seemed like a fun game. But then, I clicked on the two links Nate provided in his post and realized that there was a problem.

When you click the Weather Underground site for the actual high temperatures, it defaults to the University of Minnesota weather station. When you click on the Weather Channel site for the historical averages, it shows the averages for the Minneapolis-St. Paul International Airport. In short, he's using different stations for actuals and averages.

That really makes a difference. The average high temperature of 82.4 degrees Nate records for this summer at the University of Minnesota (June 21 through July 18) is significantly higher that the average temperature at the airport, which is just 80.3 degrees during that time. Further using the airport data for June and July, one finds that the temperature has been below average 18 times at the airport, and above average only 8 (with two days right on the number).

On 16 of the 18 times that the temperature was below average, it was below by two or more degrees, which would mean Nate would owe me $400 for those days (had he made the offer in June). On seven of the eight warm days, the temperature was more two or more degrees above normal, so I would owe Nate back $175. As of Saturday night, I would be up $225 for the summer.

(Another little nitpick on the criteria, Nate is using the astronomical Summer, which begins on the Summer Solstice, but the Meteorological summer begins on June 1. If I were to use that criteria, I'd be up $350 since the first half of June was also quite cold in Minneapolis.)

Of course, I'm not going to take the bet. For one, I don't live in Minneapolis. Secondly, my blog isn't large enough to count. Finally, even if one and two were in my favor, chances are that I'd lose out over the next two months because these things tend to even out and a long cool stretch is already behind us.

Tags: Climate Change fivethirtyeight Nate Silver