Are This Week’s Frigid Temperatures Really Colder Than Mars?

Is Duluth as cold as Mars this week? Ice on Lake Superior in Duluth, Minn. U.S. and a Martian landscape in Gale Crater photographed by the Curiosity rover. Credit: Bob King / NASA

The polar vortex-inspired cold wave pooling over the U.S. this week has broken temperature records left and right. More than once I’ve heard pink-cheeked TV meteorologists say it’s colder than Mars. Are they right?

A recent global view of Martian weather centered on the Curiosity rover longitude. The north polar cap is at top. A small dust storm fringes a large patch of water ice clouds over a high volcanic region called Elysium. Skies have been sunny with bitter cold temperatures – especially at night – where Curiosity been’s roving. Click to see a short movie of recent Martian weather. Credit: NASA/JPL-Caltech/Malin Space Science Systems

Well, sort of. Naturally it depends on where and when you poke your thermometer. A summer day on the Martian equator can see the mercury rise to 70 degrees F (20 C). Wait a minute. That means Duluth’s colder than Mars seven months a year. Summertime highs at mid-latitudes are closer to 32 F (0 F), still much nicer than what Chicagoans will experience today.

Mars is considerably colder than Earth’s because the planet is on average about half again as far from the sun as Earth. If you stand farther from the wood stove, the heat is less intense. The same is true with planets whirling around a central sun.

Mars is considerably colder from Earth because it’s both farther from the sun and has a very thin atmosphere. Credit: NASA/JPL-Caltech

Day-night temperature variations are more extreme than Earth’s because Mars’ atmosphere is exceedingly thin, less the 1% that of Earth. The atmosphere of Mars heats up quickly and reaches occasional pleasant-sounding highs, but when the sun goes down, the skimpy air can’t hold onto the heat. Temperatures plummet.

Remember that 70 degree high? At night the temperature at the same locale can dip to -100 F (-73 C). The average temperature planet-wide is around -70 F (-57 C).

Maybe the weather forecasters were referring to Gale Crater, home to the Curiosity Rover, when making their temperature comparisons. Although it’s almost winter there (solstice on Feb. 15), since the rover is near the equator the season isn’t nearly as extreme as at mid-latitudes. Indeed, the rover has recorded highs above freezing on more than half the days it’s spent on the planet. Temperatures there have been dropping as Martian fall slinks toward winter but are still relatively balmy.

Ice crystals suspended in the air during yesterday morning extreme temperatures created this amazing double halo and sundog display near Palo, Minn. The temperature was relatively balmy by Martian standards – only 27 below F. Credit: Bob King

As recently as Dec. 31, the rover recorded an afternoon high of -22 F (-30 C), very close to the -21 F high I experienced yesterday while taking pictures in Embarrass, Minn. Standing in the 25 mph wind to photograph a street scene, it not only felt colder but truly was colder than Gale Crater on New Year’s Eve.

While northern Minnesota temperatures dropped to around 30 below this morning, Curiosity bested us by a mile with a high of minus 76 F on Jan. 2. And that’s without the wind chill. Martian winds range from pleasant zephyrs to hair-ripping gales. While the average wind speed is around 20 mph, seasonal winds can whip off the poles at up to 250 mph (400 km/hr). While the thin air no doubt makes the wind chill factor not as intense as Earth’s, it’s still enough to regularly dust off the Opportunity rover’s solar panels and conjure up thousands of dust devils.

Like the weather here in the northern U.S., things have turned frigid of late in Gale Crater with highs around -76 F and nighttime lows of -193 F.

So we see, not surprisingly, that Martian temperatures are variable but generally much colder than Earth’s. If the weather-folk want to more accurately compare Mars and Earth weather, instead of cherry-picking favored times and locations, they should at least compare typical mid-latitude Martian winter highs and lows with the current winter highs and lows in U.S. mid-latitudes.

Duluth’s high and low temps Monday were -15 F and  -28 F for an average of -21 F (-29 C). At a similar latitude on Mars the average air temperature in the winter months is around -115 F (-50 C), far colder than anything we’ll experience this week whatever the meteorologists might say.

16 Responses

  1. Richard Keen

    Bob, your lakeshore looks like a view across one of the cracks on Europa. Hopefully, Duluth won’t get that cold! Now, up there in Embarrass it might…
    When I taught Earth (and planet) science I’d like to show Earth analogs to landscapes on alien worlds, like the summit of Haleakala volcano in Hawaii which looked like Mars. The view of the Los Angeles basin from Mt. Wilson resembled Titan, unfortunately (a mostly nitrogen atmosphere with an opaque hydrocarbon haze). For Europa I’d show one of our frozen (and cracked) alpine lakes in Colorado, ice domes along the shoreline of Chicago during a 20 below cold spell years ago, and, of course, some frozen soul ice fishing in upper Minnesota.
    That beautiful glassy ice in your picture would be a fine addition to any Europa show!

    1. astrobob

      About the “Europa” photo, you nailed it. I’ve used in my astronomy classes when describing that moon. How nice that Duluth can offer the analogy! I like the LA idea for hydrocarbon haze – a perfect fit.

  2. Giorgio Rizzarelli

    Hi Bob, thanx as always for your article.

    First I’m sorry for the current discomfort you’re having. In addition to unusual cold and wind, I read you’re having much snow especially near lakes (and even frost quakes).

    I read the event is probably an effect of climate change. As I read on Wikipedia, with the rapid melting of polar ice, which replaces ice with dark (absorbent) open water, the pole heated up faster (respect usually) than other parts of the globe, so polar cold air is now not confined in the pole. The permanent polar vortex is shifted from the pole toward North America, with colder air there and warmer air in the pole, respect the usual.
    This shifting possibly explains also the unusually warm temperatures we’re having here in Europe. These days we’re indeed having unusually warm temperatures (+10°C or 50°F here today) – but I can’t say if this may be due to some other cause.

    As for Mars, I agree a confrontation between Earth mid-N latitudes and Mars equatorial temperature is not fair, unless the difference of latitude is specified.

    Interestingly, speaking about Mars’ past ages when its dense atmosphere allowed stableliquid water on surface, and moderated the day/night thermal excursion, one would conclude that temperatures were generally closer to the cold average which, even in summer on equator, is well below water melting point (if I’m right, that average is about -35°C). Only a conspicuous greenhouse effect could explain an above-zero temperature and so the presence of stable surface liquid water seas and rivers, which is now well known from Mars probes data. Some scientist say the Tharsis volcanoes could explain that greenhouse effect, by emitting much greenhouse gas (including water) and making the atmosphere possibly even thicker than Earth. What do you think?

    1. astrobob

      Hi Giorgio,
      I like the Tharsis volcano explanation as well as the varying axial tilt of Mars combined to produce drastic changes in climate.

      1. Giorgio Rizzarelli

        You’re right, the varying axial tilt, I forgot about that. It would mean hotter summers but colder winters, isn’t it? So the Mars with seas was either cloudly or with extreme seasons.

        As for the polar vortex displacement effect also here in Europe, I just read a CNN interview with a meteorologist, confirming that. The current vortex displacement toward North America, in addition to your cold temperatures, probably explains Europe’s current unusually warm temperatures, and stormy conditions as well, at least in NW Europe.

        1. astrobob

          We’re all wondering where this polar vortex came from – we used to call these things cold Canadian air masses. Apparently this one’s not strictly owned by Canada 🙂 Not only has it been cold, but the winds have been fierce. The temperature is expected to finally go above 0 tomorrow (-18C). I am looking forward to it! Happy to hear your weather’s warmer.

          1. Giorgio Rizzarelli

            Yes, assumed the polar votex displacement theory is right (and Richard below underlined the flaws) we Europeans have been taking away heat from you Americans 😀 Joking aside, best wishes for better weather soon!

        2. Richard Keen

          Giorgio and Bob,
          There’s a good article on Universe Today (Bob’s other blog) about polar vortices on Venus and Saturn from 8 years ago:

          And Giorgio, I guess you’re in Italy? Don’t worry about stealing our warmth – it’s winter, and it’s supposed to get cold now and then. Our cold should help get rid of the pine beetles that have been blighting our forests, and it will force other plants to go dormant so they can prosper in the spring. Beside, there will come the day when we’ll steal your warmth!
          But I’ll confess, that -20C/-4F with hurricane force winds takes some of the fun out of searching for deep-sky objects at the limit of myh 12-inch scope, and the shaking and blurring from the winds all but destroys the Venusian crescent.

          1. astrobob

            We’re hoping the cold takes some of the wind out of our latest pest, the emerald ash borer. I’ve seen your pine beetle damage – very discouraging, all those browned trees. And speaking of taking the fun out of observing, I’ve persevered to look at the moon, Venus, variables, Jupiter and even some deep sky over the past week and a half, but I finally couldn’t handle the -20 temps and the constant wind that whips up at night.

          2. Giorgio Rizzarelli

            Yes Italy. North-East Italy precisely, Trieste, near border with Slovenia (where I often go for darker skies). Overcast here since one week, except two mornings with scattered clouds when I could get a few decent photos of the giant sunspot. Thanx again for the replies!

    2. Richard Keen

      That polar vortex argument has a couple of fundamental flaws.
      First, it’s January and there is no dark water up there in the arctic – it’s frozen over. And since it’s also night up there, it doesn’t matter how dark the ground is. See:
      Next, this weather pattern has occurred before; I could rattle off a list of dozens of similar cold waves over North America over the past 150 years, and could look up dozens more. The pattern was very common during the Ice Ages.
      Back in the 60s through the 80s, when there were some quite historic cold waves, events like this were called “Pacific-North America” patterns due to the large amplitude wave in the jet stream.
      And Third, cold air moving south replacing warm air streaming north is how the atmosphere equalizes the uneven heating between the poles and tropics. If the heat exchange didn’t happen, and the “polar cold air is … confined in the pole”, the poles would chill to absolute zero and the tropics would boil.
      The polar vortex itself is no more than the jet stream circling around the world, and is a permanent feature of the atmosphere.
      Titan, Saturn, and Mars have polar vortices, too, because all are nearly spherical, rotating planets (moons) with atmospheres that are heated by the sun.

      1. Giorgio Rizzarelli

        Richard, thank you very much for your detailed reply.
        By the way, I liked also your post above about Earth analogs of other solar system planets/moons – that’s a favorite for me.

        1. Richard Keen

          Giorgio, those earth-bound “alien” landscapes have been a favorite of mine, too, since I was a kid. Melting snow drifts on a grassy playground reminded me of some Chesley Bonestell paintings of the edge of the Martian Polar Cap in spring. Back then, nobody blinked an eye at the plants that Bonestell painted on Mars. So of course, I’d fancy myself a Martian explorer as I stomped in the slush.

  3. Guy S

    Love the double halo shot. I shot a regular, and much dimmer, halo this morning. How do you get the relatively faint halos to expose without being blinded by the sun?

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