Last post I looked at when the hottest day of the year occurs, across several thousand US weather stations. This time I’ll look at when the coldest day happens (the lowest average low).
The earliest happens on December 1st, near Savannah, Georgia. That really is an outlier, but how nice: it’s not even winter yet and you can look forward to warming weather from that point on.
A few other locations are coldest in December, mostly in the South. January is where most of the cold-weather action is, with about 85% of the coldest days. By mid-February we’re pretty much done with coldest days; what’s left is mostly just a few scattered locations in the extreme north of Alaska and the mountains of the Big Island of Hawaii. The latest coldest day happens March 3rd; interestingly, on three mountains hundreds of miles apart in California: Grant Grove (Kings Canyon), Mt. Wilson (San Gabriel mountains), and Mt. Hamilton (Diablo Range).
Here’s what it looks like in time-lapse. As with the hottest-day data from my previous post, you can see patterns in this view. At times, the coldest day appears to sweep across the country. Not sure what it means, but it’s fun to watch.
