RodneyS

On the other hand, with a high of 90 degrees at DCA today, the span of 90+ days this year since the first 90+ day on April 10th is 177 days. That's the second longest yearly 90+ span in DC history, topped only by 1907's span of 183 days (from March 22nd to September 21st.)

January-September 2013 at DCA averaged 61.6 degrees, 20th warmest on DC's all-time list, but down 3.4 degrees from last year.

The 2013 astronomical summer (June 21-September 23rd) did not produce as sharp a contrast, but nonetheless the average minimum of 69.7 degrees was good enough for 13th place all-time, versus the average maximum of 85.7 being only 47th warmest. Similarly, during the composite summer (June 1-September 23rd), the average minimum of 69.3 was tied for the 9th warmest, whereas the average maximum of 85.1 was 48th.

Quite a contrast this year, with January-August 2013 at DCA averaging 60.4, still good enough for 18th warmest on DC's all-time list, but down 3.7 degrees from last year. The 2013 meteorological summer averaged 78.3 (26th), down 2.1 degrees from last year. But the real story of the DCA summer was the sharp contrast in relative placement between the average minimum of 70.76 (5th, down only 0.58 degrees from last year) vs. the average maximum of 85.8 (54th, down 3.7 degrees from last year). To put that in perspective, the four hottest meteorological summers in DC history (2010, 81.3; 2011, 81.1; 2012, 80.4; 1980, 80.0) were also the four hottest in the exact same order with respect to both average minimum temperatures (2010, 72.4; 2011, 72.1; 2012, 71.34; 1980, 70.79) and average maximum temperatures (2010, 90.1; 2011, 90.0; 2012, 89.5; 1980, 89.3).

I agree -- thanks for the link, Ian. I think the most interesting temperature data for DCA are these: Year to Date 01/01/13 - 08/14/13 Max: 67.3 T-39th warmest Min: 51.5 6th warmest

And this year it ended on the 9th. Still, 18 consecutive days below 90 in July-August is a far cry from the last three years.

That's helpful. Another thing to note is that 2013 marks the first August to open with the first week below 90 since 2003. That year, the streak ended on August 14th.

I agree. I note as well that July 11-August 6, 2000 also featured a 27-day streak with no 90+ temperatures, and that 2000 was the coolest DCA meteorological summer since 1972.

Quite a contrast in relative positions for DCA's average maximum and overall average temperatures in July. The average July 2013 maximum was a moderate 88.3 degrees, only 47th all-time in DC weather history. However, the overall July 2013 average was 81.2 degrees, good enough for 13th on the all-time list.

I'm pretty sure that this is the all-time record. Other notable 70+ minimum streaks at DCA are: July 12-August 10, 1999: 30 days August 13-September 10, 1959: 29 days July 17-August 13, 2011: 28 days July 5-July 31, 2010: 27 days June 29-July 24, 2013: 26 days Last year just missed being the all time champ. June 28-August 15, 2012 encompassed 49 days, and only one (July 21) had a minimum below 70. So, there was a 23-day streak immediately followed by a 25-day streak.

It may be July 15-August 15, 1980, which saw 32 consecutive 70+ minimums at DCA.

June 28-July 8, 2012 vs. July 15-20, 2013 Heat Waves June 28-July 8, 2012 Avg Max: 99.5 Avg Min: 76.4 Avg Dly: 88.0 July 15-20, 2013 Avg Max: 95.5 Avg Min: 79.3 Avg Dly: 87.4 So, last year's heat wave lasted five days longer and featured record-breaking average maximum and average daily temperatures for an 11-day period. This year's heat wave's claim to fame was the highest six-day average minimum temperature,* with the last five days each reaching at least 80 -- breaking the record of four consecutive 80+ minimums set July 21-24, 2011. Also, there was one other significant difference: Last year's heat wave featured the derecho on the second day, causing many folks to be without power for one of the hottest stretches in DC history. This year, happily, power outages were minimal. * I just discovered that July 19-24, 2011 averaged almost 2 degrees higher, at 81.2. However, only four of those days featured an 80+ minimum.

Final June total of 9.97 inches at DCA fell well short of record, but did crack top twenty rainiest months in DC history, at # 19.

Correct, and it's interesting to note how much rainfall varies in this area during extreme tropical events. Here are the all-time monthly precipitation records for any month in DC, Baltimore, and Dulles, with the other one or two locations shown for perspective: September 1934: 17.45 inches in DC vs 12.41 in Baltimore August 1955 18.35 inches in Baltimore vs 14.31 in DC June 1972 18.19 inches at IAD vs 11.53 in DC and 9.95 in Baltimore

Probably so, but it's interesting to note that during the first 10 days of June 2006, DCA recorded just 0.24 inches.

It's actually not surprising that, after last year's record warmth, this year would produce sharp declines. This year's May average of 66.7 is still 0.7 degrees above the 1981-2010 May average and 1.4 degrees above the historical (1871-2013) May average. And this year's spring average of 56.5 is only 0.1 degrees below the 1981-2010 spring average and 1.4 degrees above the historical spring average.

May 2013 at DCA is finalized at 66.7 degrees, the 45th warmest of all-time, vs last year's 71.4 degrees, the 3rd warmest. This year's meteorological spring (March, April, and May) at DCA is finalized at 56.5 degrees, the 43rd warmest. That compares with last year's record-breaking spring average of 62.2 degrees. The 5.7 degree decline from one spring to the next is the second greatest in DC history, topped only by the 5.8 degree decline between 1991's 60.0 degrees and 1992's 54.2 degrees.

Interesting contrast between the Reagan and Dulles Airport records today. Reagan hit 91, beating the old DC record by only two degrees, but that was the warmest temperature in DC this early in the season since April 6, 1942, when the old Weather Bureau station at 24th and M Streets recorded that same temperature. Dulles, on the other hand, hit 89, shattering the old record by 11 degrees, but that was the warmest temperature there this early in the season only since April 7, 2010, when 91 was recorded. Further, Dulles recorded 93 on April 6, 2010.

Both DCA and IAD beat their three consecutive season low snow totals. At DCA, the most recent three seasons total 15.2 inches, compared with the previous record of 18.4 inches set in the three seasons ending in 1999. And, at IAD, the most recent three seasons total 29.0 inches, compared with the record of 29.2 inches set in the three seasons ending in 2009. So, at IAD, the previous three-year low total occurred immediately prior to the record 73.2 inches in 2009-10. Therefore, with a new three-year low total established this year, numerology tells us that next year . . . that's correct -- will set a new four-year low.

Slight change this year, with March 2013 at DCA finishing at 43.8 degrees. The 13.0-degree decline equals the record set between 1946 and 1947, when the average temperature fell from 53.0 to 40.0. Perhaps the more interesting fact about March 2013 is that the average temperature was lower than December 2012's average of 45.3. The last time March was colder than the preceding December was 1959-60.

Incorrect assumption, and so here are the revised figures: DC still beat the old record snow minimum for two consecutive seasons, but only by 1.7 inches, and IAD now actually falls short of the two-year record minimum by 1.9 inches. So, at IAD, the record remains 14.5 inches during the winters of 2007-08 and 2008-09. DCA's 2012-13 snow total of 3.1 inches is the sixth lowest of 129 DC snow seasons, whereas IAD's 12.7 inches is the 13th lowest of 51 snow seasons.

Looks like DCA is finalized today at 1.4 inches, and so the 2-inch storm streak remains alive. However, the 1-inch or less in a single day streak ended today at 789 days.

Quite a difference between this year's and last year's astronomical winters (December 21st through March 20th) at DCA. Last year's average temperature of 45.9 degrees shattered the high record by 2.2 degrees. This year's average was only 40.4 degrees, still good enough for a tie for 29th on the all-time list, but 5.4 degrees below last year.

Thanks for the link, which inspired me to check the last three snow seasons at DCA and IAD. And, yes (again assuming that we're done for this season), they also easily broke the record low snow totals for three consecutive seasons: The new DC record for that period is 13.8 inches vs. the old record of 18.4 inches set 14 years ago, and the new IAD record is 24.9 inches vs. 29.2 inches set four years ago.

Assuming that we've seen the last of snow for this season, DC beat the old record snow minimum for two consecutive seasons by 3.1 inches, and IAD (at 8.6 inches this season and 3.7 inches last season) beat the old record (set four years ago) by 2.2 inches. There is nonetheless a big difference between DCA's and IAD's 2012-13 snow seasons: DCA's displaces last season's as the third lowest of 129 DC snow seasons, whereas IAD's is only the ninth lowest of 51 snow seasons there.