D.C. Sets Record With 138 Hours Above 80°F During Brutal Nationwide Heat Wave


Total days with lows 80 degrees or higher by year at Washington, D.C. (Source: Ian Livingston, Capital Weather Gang)

The heat dome that enveloped Washington, D.C. for much of the last week, so miserable it even prompted Metro to temporarily lift its ban on passengers drinking water aboard its trains, also broke a long-standing heat record.

For over five and a half days, the temperature was least 80 degrees in D.C. This 138-hour streak is the longest on record, dating back to 1871, and besting the 128-hour streak of two years ago.

As Jason Samenow of the Capital Weather Gang notes, this record is just the latest in an “astonishingly long list” of heat-related milestones amassed over the past four summers, including: hottest three Julys, hottest three summers, most 100-degree days in a month, and longest uninterrupted stretch above 100 degrees.

Last week’s heat, combined with stifling humidity, also broke multiple records for highest minimum temperature and came close to matching the highest known dew point ever recorded.

D.C.’s warming trend over the past few years is remarkable. Capital Weather Gang found that “daily heat records have outnumbered cold records in the nation’s capital by a 7 to 1 ratio since the year 2000 and by nearly 16 to 1 in the past 3.5 years.”

Total days with lows 80 degrees or higher by year at Washington, D.C. (Source: Ian Livingston, Capital Weather Gang)

The nation’s capital was not suffering alone last week. In fact, much of the country was sweltering in above-average heat. On Thursday, at least one location in each of the Lower 48 states hit 90 degrees or higher.

Temperatures in the Northeast were five to ten degrees above normal, with New York City experiencing the highest above-normal temperatures of any place in the country. Unsurprisingly, on Friday, NYC broke its all-time record for energy use.

Maximum air temperatures (not including heat index) from July 10-19, 2013 (Source: NOAA)

A study released last year by Dr. James Hansen, one of the world’s foremost global warming researchers, and his colleagues at NASA, examined the recent uptick in heat and drought across the U.S. and identified a single culprit: man-made climate change.

In an op-ed published in the Washington Post, Hansen wrote:

This is not a climate model or a prediction but actual observations of weather events and temperatures that have happened. Our analysis shows that it is no longer enough to say that global warming will increase the likelihood of extreme weather and to repeat the caveat that no individual weather event can be directly linked to climate change. To the contrary, our analysis shows that, for the extreme hot weather of the recent past, there is virtually no explanation other than climate change.

Hansen and his colleagues found that from 1951-1980, extremely hot summers occurred only in 0.1 to 0.2 percent of the globe in a given year. But since 1981, extremely hot summers have baked about ten percent of the earth’s land area annually and in recent years, that percentage has been even higher.

In addition to posing a major threat to the nation’s energy supply and related infrastructure, increasingly common and severe extreme weather events, such as heatwaves, are a serious concern for public health.

Released earlier this year, the government’s draft National Climate Assessment had some stark predictions: Summertime heat waves are projected to become longer and hotter , whereas the trend of decreasing wintertime cold snaps is projected to continue. These changes will directly affect urban public health through increased risk of heat stress, and urban infrastructure through increased risk of disruptions to electric power generation.

Heat stress, a recurrent health problem for urban residents, has been the leading weather-related cause of death in the United States since 1986 when record keeping began. According to the draft assessment, the effects of heat stress are greatest during heat waves lasting several days or more, and heat waves are projected to increase in frequency, duration, and intensity, become more humid and cause a greater number of deaths.

16 Responses to D.C. Sets Record With 138 Hours Above 80°F During Brutal Nationwide Heat Wave

  1. Mike Roddy says:

    I lived in DC for a few years as a child (my dad was a senior staffer to the Joint Chiefs), and summers were horrible. Besides the heat, it was sticky, with tons of gnats.

    During summer visits as an adult, we were faced with a Hobson’s choice. The main escape from the heat was to head into a bar for a beer, but that could lead to a conversation with a lobbyist or Congressman- something even more horrifying than sweating outside.

  2. Dennis says:

    I clear indicator of climate change, rather than just a typical Washington, DC heat wave IMHO. In years past (I’ve lived in DC for over 40 years), we’ve always had heat waves, but it also always dropped into the low 70’s at night. But now the overnight low is signifiacntly warmer than is typical for Washington. I’m sure the deniers will blame it on the sun. However, the sun isn’t shining at that hour …

  3. Mulga Mumblebrain says:

    That reminds me of pleasant evenings spent in the ‘Evening Star’ Hotel (known to the wives of the hacks as the ‘Evil Star’) in Surry Hills, near Rupert’s Sydney Fuhrerbunker, with the old man and his cronies, where much seditious talk of Rupert’s manifest ‘eccentricities’ was bandied about by a cabal of ‘colourful characters’. My last visit, some years ago, found the old haunt yuppified execrably (or is that a tautology?).

  4. Mulga Mumblebrain says:

    Things are moving pretty quickly, is that not so? Still no action, despite really extreme instability, already. Are there any converts to my nihilistic, ‘This is meant to happen and is being deliberately engineered by the elite’ creed, yet? I’m getting more certain by the day, but still have trouble with the ‘Why?’ question.

  5. Merrelyn Emery says:

    Wasn’t DC partly built on a swamp? You would expect to meet a few swamp-dwellers, ME

  6. Maybe we should turn off the air conditioning on Capitol Hill and K Street.

  7. cwolf says:

    If you are impressed with 138 hours at >80F, hold on to your hat…
    Cuz you ain’t seen nothin’ yet.

  8. Cervantes says:

    I’m guessing that in 1877, they left the thermometer out in the sun.

    In other words, seriously, how reliable is data from that era?

  9. daniel coffey says:

    I am pretty sure that people knew about precision temperature measurement in 1877.

  10. daniel coffey says:


  11. daniel coffey says:

    Action now will not appreciably change the outcome – at this point as the GHG is already released and the energy accumulation is increasing without an off switch.

  12. Mulga Mumblebrain says:

    And the data from the 1920s up to today-were they all similarly unreliable? For Gawd’s sake, stick to tilting at windmills.

  13. Spike says:

    Monday was the hottest day in the UK so far this year too, at the end of our longest heatwave for a long time. Today I sit in my house with impressive thunder and episodically torrential rain outside.

    The Met office states an area of low pressure is expected to increasingly interact with the plume of hot, humid air resident across parts of southern Britain. Whilst preceding days will have seen relatively isolated thunderstorms, the developing set-up on Tuesday and early Wednesday, provides the ingredients for more widespread and energetic storms. Large rainfall totals, falling in short periods (perhaps exceeding 50 mm in 3 hours) and onto hard-baked ground, may lead to flooding locally, with hail and gusty winds an additional possibility.

  14. BBHY says:

    I was kind of hoping DC would hit 110F. That might be enough to pull a couple more congress critters back to reality. Probably not, but we have to maintain some level of hope.

  15. I hope the 2014 elections weed out a lot of climate science deniers (mostly Republicans)…

  16. Mulga Mumblebrain says:

    I remember a day in 1986 when Sydney got 360 mms, and places just south over 500. The dump where I lived leaked like a sieve. But that’s nothing to the rain that they’ve already had in Pakistan and elsewhere, and that to come.