RodneyS

Winter precipitation this season was actually more impressive than temperature. IAD received 12.08 inches during December 2013 through February 2014 vs a 1981-2010 normal of 8.38 inches and a 1978-79 record of 15.94 inches -- good enough for 6th all-time (relative to 51 meteorological winters there ). DCA received 12.13 inches vs a 1981-2010 normal of 8.49 inches and a 1881-82 record of 18.30 inches -- good enough for 19th all-time (relative to 143 meteorological winters in DC).

IAD finished February at 32.2 degrees , bringing the meteorological winter average to 32.9 there. That is 2.4 degrees below the 1981-2010 normal of 35.3, which means that season tied for the 15th coldest winter, and the coldest since 2002-2003 (30.7). However, it was still far behind the back-to-back winters of 1976-77 and 1977-78, which each averaged 29.0.DCA finished February at 37.8 degrees , bringing the meteorological winter average to 37.4 there. That is 1.0 degrees below the 1981-2010 normal of 38.4. However, this season was actually the 56th warmest DC winter of 143, and the coldest only since 2010-2011 (36.7). Moreover, it trailed the all-time coldest winter by 8.4 degrees. That would be the winter of 1904-1905, which averaged 29.0.

During the 2013-14 snow season, DCA and IAD have now each exceeded their three most recent snow season totals combined. For DCA, this season has seen 15.5 inches vs. 15.2 inches for the prior three seasons; and for IAD, this season has seen 30.8 inches vs. 29.0 inches for the prior three seasons.

Speaking of Top Tens at Dulles, with yesterday's 0.3 inch snowfall IAD has now recorded 30.5 inches of snow this winter, tying this season for 10th on the all-time list. Further, IAD's snow total this season has exceeded DCA's total of 15.2 inches by 15.3 inches so far, putting it within striking distance of the all-time record separation of 18.6 inches set in the winter of 1992-93, when IAD recorded 30.3 inches and DCA recorded only 11.7 inches. That season -- also an ENSO-neutral one -- more than half of IAD's snow total was recorded in March.

IAD Top Ten: 1) February 5-6, 2010: 32.4 inches 2) January 6-8, 1996: 24.6 inches 3) February 10-11, 1983: 22.8 inches 4) February 15-17, 2003: 21.7 inches 5) December 18-19, 2009: 18.0 inches 6) February 18-19, 1979: 16.3 inches 7) December 31,1970-January 1, 1971: 15.4 inches 8) March 12-14, 1993: 14.1 inches 9) February 12-13, 2014: 13.3 inches 10) December 25-26, 1969: 12.1 inches

Dulles' snowfall of 13.3 inches on February 12-13, 2014 cracked the IAD Top Ten, at #9, displacing to # 10 the December 25-26, 1969 snowfall of 12.1 inches.

IAD finished at 27.2 degrees, which was indeed the 6th coldest January there, and 6.0 degrees below the 1981-2010 normal. DCA finished at 32.2 degrees, which tied for the 39th coldest January in DC, and 3.8 degrees below the 1981-2010 normal.

IAD looks as if it will finish January with an average temperature of around 27 degrees, which would make it the coldest January since 1994 and the 6th coldest all-time. The coldest IAD Januaries: 1977 (21.0), 1970 (23.9), 1984 (25.8), 1994 (26.1), and 1982 (26.2). Bear in mind, however, that the temperature record there dates only to November 1962, and so we're talking about only 52 Januaries. DCA has not been all that cold, and will likely finish January with an average temperature of around 32 degrees, which would not be even the coldest recent January. The coldest DCA Januaries over the past 20 years: 1994 (28.8), 2004 (30.6), 2003 (31.1), and 2009 (31.7). The all-time coldest DC January was 1918, with an average of 23.7, and there have been another 30 or so years in the 144-year January temperature record that have been colder than this one is likely to be.

I would say DCA no, but IAD yes.

In that case, you are definitely in the minority among sports fans. But let me ask you this: What would it take to convince you that something more than random fluctuations were taking place?

Rodney, have you split it out before and after the move to the river location? I have now done that. First, a slight error crept into my previous calculations, as during the most recent 31 years, January 13th had a lower average temperature than January 21st six -- rather than five -- times. Thus, the percentage changes slightly, from 16.1% to 19.4%. Sorry for the error, but 19.4% remains a long ways from 63.8%. Second, regarding your question, DCA became the official DC weather location on July 1, 1945, and so the first 74 Januaries reflect the previous 24th and M Street, NW location. During those 74 years, January 13th had a lower average temperature than January 21st 48 times (64.9%), with one tie (1.4%). In the next 38 years -- prior to the most recent 31 years -- January 13th had a lower average temperature than January 21st 22 times (57.9%), with two ties (5.3%). So, the percentage did lessen somewhat immediately following the location change, but not all that much. Overall, since the location change, January 13th has had a lower average temperature than January 21st 28 times (40.6%), with two ties (2.9%).

Thanks for your comment, but I think the question remains whether something has fundamentally changed in recent years. Consider that, during the first 112 years of DC temperature records, January 13th had a lower average daily temperature than January 21st 70 times (62.5%), with three ties (2.7%). However, during the most recent 31 years, January 13th had a lower average temperature than January 21st only five times (16.1%), with no ties. Think of this situation in a sports context: Suppose a baseball or hockey team had a winning percentage of .638 over its first 112 games (counting each of the three ties as half a win), and then plummeted to a winning percentage of only .161 over its most recent 31 games. Would you say that it's more likely that those sharply varying winning percentages can be explained by: (1) random fluctuations, or (2) a fundamental change in the team's performance?

The beat goes on. January 13th reached 61 degrees this year, and averaged 46.5, vs 29.0 on January 21st. January 13th -- once the coldest January day -- has now averaged 40.5 since 1984, vs 31.8 on January 21st. Why so warm in early January in recent years, and why do the January cold waves now occur around the 21st?

In DC, I believe that it is January 25th, with 24 events. So, perhaps we can make it 25 tomorrow. December 5th, by the way, has had only ten.

Here is an odd coincidence. From the beginning of the official DC snow record in the winter of 1884-85 through the winter of 1999-2000, there was measurable snow on January 21st in only three years (1917, 0.8 inches; 1976, 0.1 inches; and 1982, 3.5 inches). However, since then there has been measurable snow on January 21st in six years (2001, 1.1 inches; 2003, 0.7 inches; 2007, 1.2 inches; 2011, 0.1 inches; 2012, 0.6 inches; and 2014, 3.8 inches).

The 2-inch DC snow drought is over, at 1091 days between the storms of January 26, 2011 and today, January 21, 2014. The previous record was only 701 days, between the storms of February 4, 1975 and January 5, 1977.

Here is a mind-boggling statistic to put our area's volatility in perspective. Nowata, OK set the all-time low temperature record in the history of Oklahoma on February 10, 2011, with a reading of -31. Exactly one week later, it recorded a high of 79 -- a 110 degree rise not from winter to summer but from one Thursday to the next!

For DC, I believe it is 1881. The high of 104 on September 7th represented a 118 degree increase from the low of -14 on New Year's Day. For DCA, I believe it is 1994. The high of 101 on June 15th represented a 105 degree increase from the low of -4 on January 19th. For IAD, I believe it is 1987. The high of 100 on August 27th represented a 117 degree increase from the low of -17 on January 28th.

IAD easily broke the lowest daily maximum and minimum records for January 7th, with 18 and 1, respectively. The maximum was the lowest since January 16, 2009 (17), and the minimum was the lowest since January 17, 2009 (0). The daily average of 9.5 was the lowest since February 5, 1996 (5.0, consisting of a maximum of 20 and a minimum of -10).

It's also interesting to note that DCA's average maximum 2013 temperature was 67.0 degrees, which was only 36th warmest all-time in DC, and down 3.2 degrees from last year (yearly decline was also 5th largest in DC history).

With a December average temperature of 42.3 degrees at DCA, 2013 averaged 58.8 there, 20th warmest all-time in DC, but down 2.7 degrees from last year, the 5th largest yearly decline in DC history.

And the IAD low of 62 beat the previous record of 61 set on that same date, while beating the previous record for December 22nd (also set in 1990) by 13 degrees. Interesting that DCA's low yesterday was 57, five degrees below the other two area airports. While 57 still easily erased the previous record for December 22nd of 49 set in 1923, it fell two degrees short of the December record of 59 set on December 5, 1973.

And the afternoon highs all eclipsed records -- 70 at IAD, 71 at BWI, and 72 at DCA.

This morning's low of 51 at both DCA and IAD tied the record high minimum at DCA and broke it at IAD. Also, BWI's morning low of 54 broke the record there.

If January is excluded, this year so far has been the 25th warmest all-time, so not that much of a change there. If you look at 1981-2013 (33 years), January-November is the 14th warmest, but the coolest since 2009, which averaged 0.4 degrees cooler through November. The coolest year through November during 1981-2013 was 2003, which averaged 58.0 degrees, or 2.3 degrees cooler than this year so far.