July 20, 1930 – Hottest Day On Record In Washington DC

On this date in 1930, Washington DC reached 106F – the hottest temperature ever recorded there. Most of the eastern half of the US was above 100F.

The closest USHCN station to DC in Virginia is at Lincoln. It is close to where I stay when I am in Maryland. They had nineteen days over 100F in 1930, and eighteen in 1931. One hundred degree days were much more common in the DC area prior to 1960, and have become less frequent as atmospheric CO2 has increased.

Things have changed though. The Washington Post now believes that temperatures ranging from 86 degrees to 98 degrees are “serious triple-digit heat.” Apparently math isn’t their strongest skill.

Models hinting at serious, triple-digit heat wave late this week in Washington – The Washington Post

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10 Responses to July 20, 1930 – Hottest Day On Record In Washington DC

  1. Nicholas Schroeder, BSME, PE says:

    Ah yes, heat waves and air conditioning.

    Is space cold or hot? There are no molecules in space so our common definitions of hot/cold/heat/energy don’t apply.

    The temperatures of objects in space, e.g. the earth, moon, space station, mars, Venus, etc. are determined by the radiation flowing past them. In the case of the earth, the solar irradiance of 1,368 W/m^2 has a Stefan Boltzmann black body equivalent temperature of 394 K. That’s hot. Sort of.

    But an object’s albedo reflects away some of that energy and reduces that temperature.
    The earth’s albedo reflects away 30% of the sun’s 1,368 W/m^2 energy leaving 70% or 958 W/m^2 to “warm” the earth and at an S-B BB equivalent temperature of 361 K, 33 C colder than the earth with no atmosphere or albedo.

    The earth’s albedo/atmosphere doesn’t keep the earth warm, it keeps the earth cool.


    “The first design consideration for thermal control is insulation — to keep
    heat in for warmth and to keep it out for cooling.”
    “Here on Earth, environmental heat is transferred in the air primarily by
    conduction (collisions between individual air molecules) and convection
    (the circulation or bulk motion of air).”

    Oops! WHAT?! Did they forget to mention RGHE “theory?” Global warming? Climate change? Bad scientists!
    Oh, wait. These must be engineers who actually USE science

    “This is why you can insulate your house basically using the air trapped
    inside your insulation,” said Andrew Hong, an engineer and thermal
    control specialist at NASA’s Johnson Space Center. “Air is a poor
    conductor of heat, and the fibers of home insulation that hold the air still
    minimize convection.”
    “”In space there is no air for conduction or convection,” he added. Space
    is a radiation-dominated environment. Objects heat up by absorbing
    sunlight and they cool off by emitting infrared energy, a form of
    radiation which is invisible to the human eye.”

    Uhh, that’s SPACE NOT EARTH where radiation rules.

    “Without thermal controls, the temperature of the orbiting Space
    Station’s Sun-facing side would soar to 250 degrees F (121 C), while
    thermometers on the dark side would plunge to minus 250 degrees F
    (-157 C). There might be a comfortable spot somewhere in the middle of
    the Station, but searching for it wouldn’t be much fun!”

    121 C plus 273 C = 394 K Ta-dahhh!!!!!

    Shiny insulation keeps the ISS COOL!!!! Just like the earth’s albedo/atmosphere keeps the earth COOL!!! NOT hot like RGHE’s BOGUS “Theory.”

    • Ed Bo says:

      Begone, troll!

      Seriously, take some actual thermodynamics and heat transfer courses and come back in a few years with some real knowledge, rather than spamming unrelated threads with the same cut-and-paste paragraphs that just demonstrate your ignorance.

      • Nicholas Schroeder says:

        So my BSME and 35 years of actual real world heat transfer and thermo applications missed something. Well step right up, clarify, elucidate. Detail the errors of my ways.

      • Nicholas Schroeder, BSME, PE says:

        Ed Bo

        Over 3,200!! (up 1,400 since 6/9) views on my WriterBeat papers which were also sent to the ME departments of several prestigious universities (As a BSME & PE felt some affinity.) and a long list of pro/con CAGW personalities and organizations.

        NOBODY has responded explaining why my methods, calculations and conclusions in these papers are incorrect. BTW that is called SCIENCE!!

        SOMEBODY needs to step up and ‘splain my errors ‘cause if I’m correct (Q=UAdT runs the atmospheric heat engine) – that’s a BIGLY problem for RGHE.

        Step right up! Bring science.




        And the counters still ticking.

        That NASA engineer ‘splained why UAdT works on earth but not on the ISS.

        So ‘splain scientifically why and how I’m wrong or piss off and go troll your own self.

        • Ed Bo says:

          Oh, where to start?

          First, for the purposes of radiative heat transfer, space is exceedingly cold. It behaves like a blackbody at 3K (precisely 2.725K +/-0.001K in all directions). The cosmic microwave background radiation we received from all directions is indistinguishable in magnitude and spectrum from that which a blackbody at this temperature would produce — only 3 microwatts per square meter.

          Now, you can have the philosophical and semantic debate as to whether space is really “at” this temperature, or whether this is just an “effective blackbody temperature”. (Technically, it is not true that “there are no molecules in space” — the density is incredibly low, but the extent is incredibly vast). But for the purposes of calculating radiative heat transfer between earth and space, you must treat space as incredibly cold (2.725K) to get any accurate answers.

          In my engineering heat transfer classes, we were taught to treat the effective blackbody temperature of a clear night sky (in temperate zones) as -20C (253K). So your upward facing surfaces are in radiative exchange with this temperature, not with the 3K they would be in exchange with with an IR-transparent atmosphere. Big difference!

          Now, because the density of space is so low, there is no significant conductive or radiative heat transfer between the earth/atmosphere system and space — only radiative. You say, “that’s SPACE NOT EARTH where radiation rules”. But earth is in space, so the overall heat transfer between earth and the rest of the universe is 100% radiative.

          You say there is ” 958 W/m^2 to “warm” the earth and at an S-B BB equivalent temperature of 361 K”. This would only be true if this were the constant flux over the entire earth! In reality, the vast majority of the earth’s surface NEVER sees this solar flux, and only a small zone of the the tropics ever sees this intensity momentarily at solar noon.

          It is simple high school geometry to see that the average solar flux intensity is 1/4 of this (a sphere has 4 times the area as one side of a disk of the same radius), which brings the average intensity to about 240 W/m^2. Why can’t you understand this point that high school students get easily???

          Even if the temperature of earth were distributed evenly, if the surface radiated directly to space, the temperature could not be above 255K. With variations in temperature, Holder’s Inequality tells us that the average temperature would be lower. The moon’s average surface temperature is about 190K, and it has a lower Bond (solar)albedo than the earth. Yes, its maximum temperatures are greater, but overall, it is much cooler.

          You say: “The earth’s albedo/atmosphere doesn’t keep the earth warm, it keeps the earth cool.”

          Here, you are completely confusing the reflection of shortwave solar radiation with the absorption of longwave terrestrial radiation. The Bond albedo (percentage of reflection of solar radiation) is overwhelmingly due to liquid water in the form of clouds, and solid water in the form of snow and ice on the surface, not to atmospheric gases.

          On the other hand, the absorption of longwave terrestrial radiation is largely due to atmospheric gases (CO2 and H2O), with a significant contribution from clouds as well.

          Enough for now, but you are substantially wrong on every point you bring up. I would reject this completely from any of the undergraduate engineering students I teach.

  2. RAH says:

    BTW the solar disk is once again spotless and speckless.

  3. Andy DC says:

    The alarmist claim is that Reagan National Airport (DCA), the main Washington, DC station, has shown a lot of warming during summer. The Lincoln data would seem to make the DCA data look highly suspect.

    Yes, we are having some miserable heat and humidty in the DC area, but that is nothing at all unusual in late July.

  4. garyh845 says:

    Tony – have you ever graphed up Los Angeles like this? We’ve had a pretty good stretch of warmer than normal weather (big deal) and there’s been a lot of attention in the media to it, with Gov Brown pushing his latest radical agenda.

    In looking at – http://www.laalmanac.com/weather/we04.php – looks like there are still about 25 daily high temp records which were set prior to 1900 still standing, for the summer months of June – August (92 days). That’s a large percentage.

    On the sidebar, there would not have been any ‘urban heat island effect’ at the time, what-so-ever. To tie those old record highs today, they should be adjusted upward some 4-6 degrees F – ya think?

    PS – 70 miles. Wow!

  5. Buck Turgidson says:

    I live in Washington. It’s not going to hit triple digits this weekend. This is more junk science, arm waving hysteria BS from the idiots @ WaPo. These people are the picture of irresponsibility, they exaggerate climate conditions and stats *all the time* and no one ever calls them on it, esp themselves. No accountability, and no credibility. The paper would be in the toilet if not for Bezos $$$$$$

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