Awhile back I stumbled onto an interesting old Tribune infographic about murder and weather:

What's interesting to me about it, besides the correlation between heat and murders (it exists, although school being out of session plays a role), is that December and January have higher totals than February and March, even though they have lower temperatures. February's shorter, but it's not that much shorter.

And this year's February homicide totals have drastically declined from last month—according to Tracy Swartz at RedEye, there were 43 homicides this January, and they've tracked 14 so far this month. Just following along on Twitter and in the news, things have seemed noticeably quieter.

So I was curious if that above trend held up, and added up the 2002-2012 murder totals by month for December, January, February, and March, aka the crappiest months in Chicago.

Here's the average per month, and per day:

December: 34.6/1.11
January: 29.5/0.95
February: 24.9/0.80
March: 36.2/1.17

It's weird. February's warmer, there's less snow, and it's no more damp than January. What gives? My only theory, which comes from personal experience as much as anything, is that by February people are finally done with going outside—done with the cold and the dark, and for better and worse, waiting for spring to reemerge.

Photograph: Chicago Tribune