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Posted at 9:30 AM ET, 09/ 1/2010

Summer 2010 hottest on record in Washington

By Ian Livingston

Jun-Aug temperature secures spot by over 1 degree!

* How much more heat? Full Forecast | Hurricane Tracking Center *

2010 compared to the previous five high summer temperature averages at Washington, D.C. The three-month period was a stunning 4.3 degrees above average.

The broken heat record keeps on playing. Warmest astronomical spring... warmest June... warmest July (tied)... no, not quite there for August... But yes, warmest meteorological (Jun-Aug) summer.

Those who've lived it don't need the Capital Weather Gang to know it has been a toasty one. Still, it's worth noting just how toasty. Washington, D.C. did not only top the previous three-month record, it pretty much crushed it with its 81.3 degree average. Beating a seasonal record by 1.3 degrees with a departure from average of 4.3 degrees is, however you slice it, extremely impressive.

Keep reading for more stats about D.C.'s historic summer heat.

Daily temperature departures (rounded) at National Airport from June through August. Departures (warm: red, cool: blue) are calculated by comparing the average temperature of the day to a 30-year "normal" temperature for that day based on readings from 1971-2000. Source: NWS Baltimore/Washington.

The monthly averages of June, July and August (80.6, 83.1 and 80.1 respectively) represent the first time that one year has seen three months with an average above 80 degrees. August's 80.1, while playing a supporting role in the summer scorcher, ranks a little lower down the scale than the record June and July, coming in at #9 (tied) all-time.

The 2010 average summer high temperature was 90.2 degrees, the first time we've ever averaged above 90 through the period. 52 days reached 90 degrees or higher. 18 of those days occurred in June (tied for June record), 21 in July and 13 in August. Four years saw more 90 degree days from June through August, with the most being 55 in 1988.

When comparing lows, 2010 also stands out. From June 1 to August 31, 71 days (or 77 percent of the summer) had a low of 70 degrees or higher. This ranks well above #2 (2005) when 61 days had a low 70+. The previous warmest summer on record of 1980 witnessed 59 such days. The average June-August low was 72.4 and 2010 is the first time D.C. has seen four daily lows above 80 degrees in one year.

September's average for 90+ days is 3.3, and the record is 14 during 1980. Recently, D.C. saw as many as 6 in 2008 and 4 in 2007 -- last year there were none. Including today's (Sep 1) sure 90+, National will stand at 58 for the year. 1 more 90+ is needed to tie #2 all time, with the record 67 in 1980 still a reach but maybe not totally unattainable.

2010, a year of records:

  • It's history: Winter 2009-2010 snowiest on record

  • February recap: Once in a lifetime snows

  • 2010: Warmest spring on record for Washington D.C.

  • June 2010 sets warmth record in Washington D.C.

  • July warmth record tied at Washington, D.C.

  • Is 2010 the most extreme year for D.C. weather?
  • We will do a larger recap of the whole 2010 warm season at a later date. In the meantime, check out CapitalClimate for some other nifty stats on meteorological summer. Finally, the New York Times reports New York City also had its hottest summer on record.

    By Ian Livingston  | September 1, 2010; 9:30 AM ET
    Categories:  Extreme Heat, Local Climate  
    Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati   Google Buzz   Previous: Forecast: A new month... same old heat
    Next: Hurricane Earl watches for VA/MD/DE beaches



    Posted by: gjjg4dgd | September 1, 2010 9:39 AM | Report abuse

    gjjg4dgd - how are you faring in this extreme DC summer??

    Posted by: Camden-CapitalWeatherGang | September 1, 2010 9:58 AM | Report abuse

    I know it's been much hotter than the past few summers...but I thought you all said 1980 had FAR more over 90 days? If that's true, how could this be the hottest summer ever?

    Posted by: silencedogoodreturns | September 1, 2010 10:00 AM | Report abuse

    I agree with silenced. I want to see the data for astronomicalsummer --roughly June 21-Sept 21 before we proclaim this the hottest summer ever (and I realize that CWG did say it was the hottest "meteorological" summer, which I think is a specious indicator) .

    The high temperature on the first day of fall in 1980 was 101 degrees. I sure don't want that to happen again but having endured the summer of 1980 in D.C., I think 2010, while horrible, isn't yet the hottest summer ever hereabouts.

    Posted by: JerryFloyd1 | September 1, 2010 10:35 AM | Report abuse

    silencedogoodreturns, while 90 degree days is an easy metric to use it does not necessarily tell the whole story month to month or season to season. Temperature averages (lows and highs) are more important. 1980's avg Jun-Aug high/low was 89.3/70.8 (#2 for both) compared to this years 90.2/72.4 (#1 on both). Also, we are currently ahead of 1980 for 90+ days season-to-date, but it had an extremely warm September.

    Posted by: Ian-CapitalWeatherGang | September 1, 2010 10:35 AM | Report abuse

    Jerry, specious is probably a little strong since this is how 'summer' averages are calculated by every NWS office in the country.

    Posted by: Ian-CapitalWeatherGang | September 1, 2010 10:39 AM | Report abuse

    Hey how about that phony Global Warming now? still think it's fake? stupid, clueless idiot Republicans.

    Posted by: Hillary08 | September 1, 2010 10:48 AM | Report abuse

    Meteorological Fall should be a National holiday. Really, I'm serious. To be able to turn that calendar from August to September is such a relief, especially this year. Now CWG, I'd love a little peek past the 6-day forecast you have listed on the page...hotter, cooler, staying the same?

    Posted by: authorofpoetry | September 1, 2010 10:57 AM | Report abuse

    the end is near

    Posted by: jiji1 | September 1, 2010 10:59 AM | Report abuse

    Hillary08 - "Global warming" is too broad. The current term seems to be "global climate change," which covers both unusual weather patterns, including extremems of heat and cold.

    Republicans aren't the only ones who doubt that we have enough scientific data to definititvely say that humanity has caused an artificial global climate change. I'm not a Republican, for example, and I say "horse crap."

    Finally, what happened to all those folks yelled at everyone who pointed at the unusually long and bitter cold winters and snow storms, claiming them as proof that "global warming" isn't real? I heard the phrase "weather is not climate" so often I thought about buying the bumper sticker. Now, though, it seems that an unusually hot summer is "proof."

    Make up your mind. Better yet, read a bit more about scientific method and statistical trends and come back with an opinion that actually has some weight to it. If you want to call someone an idiot, you'd best be sure you know what you're talking about.

    Also, how about we drop the generalizations? Not all Republicans agree on this, and not all who think it's a load of manure are Republicans. Blanket assumptions are the problem all around in this useless debate.

    Posted by: kevintumlinson | September 1, 2010 11:00 AM | Report abuse



    Posted by: buckeye293 | September 1, 2010 11:12 AM | Report abuse

    CWG, did I miss the fall outlook or is it still upcoming?

    Concerning the definition of seasons...

    If you click that Warmest Spring article linked in the post the Sterling Office of NWS clearly dabbled in astronomical season calculations...

    Posted by: spgass1 | September 1, 2010 11:13 AM | Report abuse

    " a 30-year "normal" temperature for that day based on readings from 1971-2000."

    Has anyone calculated the delta of that over the past 50 years or so? That is, 1951-1980, 1952-1981,...,1981-2010.

    Posted by: wiredog | September 1, 2010 11:21 AM | Report abuse

    kevintumlinson - "how about we drop the generalizations? Not all Republicans agree on this, and not all who think it's a load of manure are Republicans. Blanket assumptions are the problem all around in this useless debate."

    Kevin, the evidence is easily found that republicans in positions of power and their constituents are far more likely to distrust the position held by the majority of climate scientists.

    What we are seeing is the knee-jerk rightists, trapped in a position of their own making, trying to rewrite history - "b-b-but, I was never really against global climate change!!!"

    The republicans (or tea partiers), and their corporate base (fossil fuel industries) have been trying to shape this conversation for a while now, employing some the same spin-meisters that were used to misinform people about the hazards of smoking.

    refs. below. Plenty more easily available via Google.

    Posted by: markzark | September 1, 2010 11:26 AM | Report abuse

    spgass1, they did note astronomical spring this year but that was the first I recall seeing something like that (not that it has not been mentioned before). But if you look at the official record-keeping you see no mention of any astronomical seasons.

    Posted by: Ian-CapitalWeatherGang | September 1, 2010 11:31 AM | Report abuse

    I just want the heat to go away :*(. Bring me some highs in the 60s and 50s, please??

    Posted by: sigmagrrl | September 1, 2010 11:43 AM | Report abuse

    sigmagrrl - working on this. I want it too! Give us just a few more weeks.... (ok maybe two months lol)

    Posted by: Camden-CapitalWeatherGang | September 1, 2010 12:17 PM | Report abuse

    Here on the West Coast of North America, aka, the United States, Southern California has experienced the COLDEST Summer on nearly 100 years, which has NOT been reported on the National media circuit nor in the biased Climatic reports in order to continue the stoking of the LIES that are "climate change" and "global warming."

    Also, this bogus report DOES NOTE include the recent reports from the RECORD cold temperatures of the Western Seaboard of South America. Just last week, reports were showing that the average high temperatures of Peru, Chile and Argentina were nearly 20 degrees Farenheit below normal due to a severe shift in Antartic cold air and sea currents.

    Plus, just this week, the UN has reported that its reporting for "climate change" needs to be more accurate in order to be more credible, since it admitted that there was JUNK science data in its earlier reporting in 2005 to 2007.

    It's really simple SIMON, to understand that Man can cause vast pollution and environmental damage, however, Man cannot control the climate nor change it.

    Think about morons, let's say for argument Man has been on the planet as we know it for 50,000 years. Many ice ages and warming cycles the Earth has encountered were millions of years prior to Man.

    Please for the sake of Truth in Science, stop the bogus lies of the status. This is just a scare-tactic ponzi scheme and all that have profited by it, Al Gore and others, should be indicted like Bernie Madoff.

    Now back to my last days of Summer in San Diego, where we just might be able to take off the sweatshirts for Labor Day weekend, because we will be entering a "more normal" Summer weather cycle of 80's on the beach and 90's in the coastal plain, instead of the 10 to 20 degrees below normal from June to yesterday, August 31.

    Posted by: hawkhill_us | September 1, 2010 12:40 PM | Report abuse

    @Ian, "meteorological whatever season" is to me a contrived term, probably cooked up by bureaucrats (and the sort of terminology that drives some right wingers up the wall).

    Once we have the data for the period between the summer and fall soltices, and this data indicates the warmest summer on record has occured, then I'll be a believer.

    (Which is not to deny it's been a brutally summer hereabouts, that global warming is on the verge of, or maybe already is, running amok, etc.)

    So I'm hoping CWG will publish comparative "almanac" summer data on Sept 22 and we can see how it synchs with the "meteorological" summer data.

    Posted by: JerryFloyd1 | September 1, 2010 12:53 PM | Report abuse

    Sorry, data between the summer soltice and fall equinox is what I meant to say in the above post.

    Posted by: JerryFloyd1 | September 1, 2010 12:56 PM | Report abuse

    Hawk, for the sake of truth in science, can you provide data for one day from june to septemeber that was 20 degrees below normal. You're obviously entitled to your beliefs, but making up data to support your own claim is the very evil you are accusing "us" of doing.

    Posted by: Brian-CapitalWeatherGang | September 1, 2010 1:02 PM | Report abuse

    Hey Hawk, I mentioned the West Coast chill recently here. We are an East Coast blog so perhaps it has not gotten the due you expect. But most of the world has been warm recently and cooler weather in the west is somewhat common during a developing Nina.

    Posted by: Ian-CapitalWeatherGang | September 1, 2010 1:06 PM | Report abuse

    Some of these posts ought to be dropped...or shifted to the Post's "Politics" blog...there's too much extreme right posting here. [I can warn the Right on one thing though...don't tamper with my monthly Social Security it is, I'm paying Federal income tax on a large portion of it...but this talk of "Social Security reform" by the "tea party" fringe scares me!] for climate, we can still hit ninety until Oct. 11...and possibly later, considering that some of those mid to late October record highs stand at 89 degrees. The 90-degree day recorded on Oct. 11 was on Oct. 11, 1954 during the run-up to a direct hit on this area by Hurricane Hazel four days or so later. Unfortunately we didn't have our sophisticated computerized model runs or model ensembles back in "Fifty-Four" when Hazel hit, so it's impossible to determine how big the weather hype for this approaching storm was. Based on what I'm hearing now about Earl and what we heard a few years back about Isabel, the pre-strike hype for Hazel, if it hit on, say, Oct. 15, 2010, would be big enough to close all schools, Federal and private offices, not to mention Metro [which has a hard enough time dealing with a NORMAL rush hour these days!] There was no Metro, of course, during 1954, though I do recall seeing old TV footage of drenched Federal employees on the afternoon Hazel hit waiting with broken and inverted umbrellas for the old Shirley Highway express buses at or around the corner of 14th and Constitution NW. It's even possible that NO federal offices were closed that day; as I recall, Hazel moved up the coast very quickly and struck this area by surprise. Hazel was also highly unusual in that hurricane and strong tropical-storm force winds moved a considerable distance inland. I believe that Reagan National recorded sustained winds of 65 to 73 mph with a high gust of 97 mph that afternoon. This was probably the worst hurricane hit on Washington, D.C. during historic times.

    Posted by: Bombo47jea | September 1, 2010 1:26 PM | Report abuse

    @Bombo, agree re: Social Security (and Medicare). Leave it alone!!

    So this post has a weather-related focus, when I lived in Wilmington, NC in 1960 the locals were still buzzing about Hazel, which made U.S. landfall just SW of Wilmingon.

    After Donna, a serious, scary blow, the locals said, "aw, this weren't nothing. Now, Hazel, she was REAL hurricane."

    Posted by: JerryFloyd1 | September 1, 2010 1:40 PM | Report abuse

    while i agree w/your sentiment about crazy right wingers, we needn't censor their posts. in fact, their posts can serve the useful function of highlighting the irrationality and emotion behind their posts.

    well said...well said.

    the parallels with the 60s/70s smoking lobbyists are striking....and should be edifying...but don't seem to be. we're a nation in denial: about our budget, about our obesity, and about climate change.


    some "high"lights:
    "The July worldwide land surface temperature was 1.03°C (1.85°F) above the 20th century average of 14.3°C (57.8°F)—the warmest July on record."

    For the year-to-date, the global combined land and ocean surface temperature of 14.5°C (58.1°F) was the warmest January-July period on record. This value is 0.68°C (1.22°F) above the 20th century average.

    now, these are GLOBAL, not just for southern california. noaa doesn't have the june/july/august figures up yet - i'll keep you posted though.... (wanna bet that the 2010 summer, california included, comes out in the top 3 on record, GLOBALLY?)

    Posted by: walter-in-fallschurch | September 1, 2010 1:51 PM | Report abuse


    GLOBAL land and ocean temperatures for the first half of 2010 were the WARMEST on record. An unprecedented heat wave in Russia killed hundreds, and millions have been displaced by catastrophic floods in Pakistan and China. Perhaps this is all just an inconvenient coincidence, or the libruls at the Weather Company making mischief. I know you have some excellent explanations!

    All sorts of strange weather, including the cold off South America is caused shifting air and water patterns that are the result of our rapidly changing climate. And don't you worry. This summer has been cool, but the West Coast will NOT be spared in the coming years.

    Posted by: abulinix | September 1, 2010 1:53 PM | Report abuse

    There is one indicator that needs to be factored into the "warmest ever" mix and that is cooling degree days. There were 2,006 CDDs in 1980. The 2010 YTD figure as of 8/31/10 is 1,759, admittedly well above the YTD average of 1,299.

    I don't want to sound like one of those "Now Hazel was a REAL hurricane" folks in 1960, but until all data conclusively proves this was the warmest (almanac) summer on record hereabouts, I'm holding out.

    Posted by: JerryFloyd1 | September 1, 2010 2:15 PM | Report abuse

    Jerry, was the heating degree days metric around before cooling degree days? Just wondering if that's the reason they use 65 for the CDD calculation. It obviously still works for an apple-to-apples comparison, but I don't know anyone who keeps their thermostat on 65 in the summer.

    Posted by: spgass1 | September 1, 2010 3:10 PM | Report abuse

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