It hit 17 degrees in D.C. this morning for the first time since January 24, 2011. How cold is that really for the D.C. area?
I took the picture above while on an 8 mile run through D.C. Yes, my girlfriend thinks I'm nuts, my friends think I'm nuts, and my coworkers definitely think I'm nuts. I mean, yes, it was only 17 degrees outside when I started (which happens to be one of the coldest days in a year) but how cold is that compared to normal though? Let's take a look.
I went ahead and looked at the past 4 years of data for daily lows in December through February (typical Winter months or "meteorological winter"). Something I found interesting is that since 2008 (including Dec. 2007), only 13 days had low temperatures at or below 17 degrees. Out of the 361 days of Winter since 2008, only 3.6% of the days had lows of 17 degrees or less. 17 degrees for a low also ties for the 9th coldest low temperature over that same period of time.
- Another look at the World War 2 Memorial this morning
Now why did I specifically choose that period of time? Simply because I didn't want to mention February 2007. Not because I am some global warming enthusiast but because it would make the last 4 years look like hogwash. February 2007 had 9 days in the month with lows at or below 17 degrees. That actually comes to 32% of the month! On a side note, that month was 7 degrees below normal for temperatures, so just a bit of an outlier...
Delving a bit deeper into this matter, I went ahead and checked out the temperature departures for the winters I examined. What's crazy is that 3 out of the 4 were actually below normal temperature-wise at Reagan National. I had no clue about that! Just a hunch, but I think this winter will be above normal. Over the past 4 winters, our temperature departure is +0.1525. Talk about close to normal!
Find the normal records and extremes for Reagan National here, and quit complaining, here's November 2011 for Fairbanks. They averaged -16.8 degrees for lows that month!
Conclusions to take from this: It really hasn't been that cold over the past 4 years, but then again that is just the D.C. climate. The record lows are about 20 degrees colder than the lows we had last night, with the lowest temperature recorded in January at -14 degrees back in 1881. On another note, 16 of the record lows in January are from the 1800's, while 22 date from 1935 or earlier. I don't really think these numbers account for the massive urbanization the region has seen and believe our low this morning would have been even lower without the heat island. Final thoughts... this is about typical for a winter in D.C. as these swings are more than common. I'd expect two to three more during the rest of the winter.
Coldest Days in the Past 4 Years:
1. January 17, 2009: 8 degrees
2. January 16, 2009: 11 degrees
3. February 5, 2009: 15 degrees
4. February 8, 2008: 16 degrees
Tie - December 22, 2008
Tie - January 3 and 31, 2010
Tie - February 7, 2010
9. December 23, 2008: 17 degrees
Tie - January 15, 2009
Tie - February 6, 2009
Tie - January 22 and 24, 2010
Tie - January 4, 2012