Our Best March Ever… Statistically Speaking

Crunching the numbers in Excel, March 2011 had the best weather of any March that we have ever had. For the first time ever, I will share data from my Washingtonian Weather Index. Here is the rankings for our top 10 Marches.

Place	Month	Year	Score
1	March	2011	81.68%
2	March	1989	81.30%
3	March	1983	79.91%
4	March	2003	80.40%
5	March	1984	79.51%
6	March	2007	79.50%
7	March	1968	78.42%
8	March	1961	78.79%
9	March	1974	78.40%
10	March	1957	78.68%

On my all-time list of best months, March 2011 is ranked 13th. Here are the top 20.

Place	Month	Year	Score
1	January	2006	86.09%
2	April	1993	84.77%
3	November	1953	84.53%
4	November	1999	83.03%
5	October	1990	82.34%
6	November	1983	83.08%
7	January	1953	83.6%
8	February	1961	83.08%
9	November	1998	82.33%
10	November	1954	81.5%
11	February	1958	0.8157
12	November	1963	82.13%
13	March	2011	81.68%
14	December	1950	81.9%
15	October	1950	80.86%
16	November	1965	80.91%
17	October	1956	80.74%
18	March	1989	81.3%
19	February	1983	80.76%
20	January	2010	80.71%

In 2008, Scott Sistek posted to his blog about a weather index created by a reader of his. In the post, Another new index says past summer was Okey-Dokey, he provided links to weather data and opened the door for others to create their own indexes (or is it indices). Although I hadn’t shared it with anyone, I actually did make my own index.

Let me explain my opinion of the so-called Summer Satisfaction Index. The idea was obviously an attempt to put an objective measure on a subjective issue. What makes for ideal weather will definitely vary between people. The Summer Satisfaction Index put an emphasis on its creator’s preferences. He likes warm and sunny. I like cool and drizzly. His index simply didn’t work for me.

I have created my index using averages and extremes. Since our averages are very close to what I view as ideal, I have used those in my calculations. This means that the numbers that I’m sharing can change over time. I have also used percentages, where a perfect score would be 100%. I feel that these averages represent why I love Washington weather and will likely be hated be foreigners. That is why I call it the “Washingtonian Weather Index.”

I have plans for this index. I intend to share the details in the future. For now, I will remain quiet. If you would like to make your own index, you can find data from June 7, 1948 through June 30, 2008 at:
http://komonews.s3.amazonaws.com/seatac_daily.txt

I have been using a site that shows months of information starting January 1998 for later months. This site can be found at:
http://www.beautifulseattle.com/clisumm.htm