The Daily Parker

Politics, Weather, Photography, and the Dog

Volatility

Late winter and early spring in Chicago have always had some ups and downs in temperature. This year, with a week left to go in meteorological winter, has been nuts.

It got down to -2.8°C just before 8am today. That's not too far from normal—for March 8th. But here are the temperatures over the past 10 days:

Date High Low Avg
Tue Feb 20 18.9°C 1.1°C 10.0°C
Mon Feb 19 15.6°C 2.8°C 9.2°C
Sun Feb 18 5°C -11.1°C -3.1°C
Sat Feb 17 1.7°C -8.3°C -3.3°C
Fri Feb 16 2.8°C -6.7°C -1.9°C
Thu Feb 15 8.9°C 3.3°C 6.1°C
Wed Feb 14 6.7°C -4.4°C 1.2°C
Tue Feb 13 1.7°C -13.9°C -6.1°C
Mon Feb 12 -2.8°C -15.6°C -9.2°C
Sun Feb 11 -5.6°C -11.7°C -8.7°C


But looked at another way, using the normal temperatures for each day in Chicago, we've been all over the calendar:

Date Felt like
Tue Feb 20 May 2 Mar 30 Apr 17
Mon Feb 19 Apr 17 Apr 9 Apr 13
Sun Feb 18 Mar 2 Brrr! Feb 11
Sat Feb 17 Feb 13 Feb 4 Feb 11
Fri Feb 16 Feb 19 Feb 16 Feb 16
Thu Feb 15 Mar 19 Apr 12 Apr 6
Wed Feb 14 Mar 9 Feb 26 Mar 6
Tue Feb 13 Feb 13 Brrr! Brrr!
Mon Feb 12 Brrr! Brrr! Brrr!
Sun Feb 11 Brrr! Brrr! Brrr!


In other words, yesterday's high temperature felt like April 30th; the low felt like March 30th; but the overall temperature of the day felt like May 19th. (Where it says "Brrr!" the temperature was below the normal temperature for any day of the year. In other words, it felt like mid-January on a bad day.) Also: nice going, February 16th! Totally normal day in February.

I should point out, these are the 1981-2010 normals. I'll leave it as an exercise for the reader to recalculate these values using earlier normal sets; 1951-1980 would be particularly interesting, I should think.

It's all part of the fun in a continental climate that has tons more energy, and thus volatility, than it had in centuries past. And thanks to continued anthropogenic climate change, we will continue to have winters that whipsaw between frigid and spring-like for a few decades, until Chicago's climate settles into a subtropical pattern where it rarely freezes. If you remember what Tennessee or North Carolina was like 50 years ago, that's where Chicago is headed 50 years from now.

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