06 January 2014

From extremely cold to extremely warm, by the numbers

At this moment, the temperature difference between Saint-Aignan, where I live now, and Urbana, Illinois, where I lived for several years in the 1970s and still have good friends, is 50 degrees Fahrenheit. And this is despite the fact that Saint-Aignan is several hundred miles farther north than Urbana.

According to the weather widgets on my Windows desktop, it's 0ºF in Urbana right now — that's extremely cold but far from unheard of — and it's +50ºF here in the Loire Valley — unusually warm for early January but, again, not unheard of. (For the Fahrenheit-challenged, that's –18ºC in Urbana and +10ºC here in Saint-Aignan.)

Autumn in the village

It's been interesting to listen to the reports on the French TV news about the current cold wave in the northeastern U.S. The other day, Claire Chazal on TF1 reported, in vague terms, that temperatures in New York and New England were « en dessous de zéro » ("below zero"), which was, she said, the coldest they had been in decades. People here might draw the conclusion that Chicago, New York, and Boston lie in a tropical climate zone, if those are unusually low winter temperatures.

Golden leaves

Chazal was talking about degrees Fahrenheit, but must not have been aware of that fact. In degrees F, "below zero" is frigidly cold. But zero on the Celsius scale is equal to +32ºF, so "below zero" in Celsius might be, say, +30ºF. That's not very cold in New York or Boston. People listening and who were thinking about it must have been mystified. In fact, the temperatures were (and are) –25ºC in places like Chicago today.

I'm worried that all that cold air might end up crossing the Atlantic and putting us in the deep freeze here in the northern half of France in a few days.

As I said yesterday, this week I'm just publishing some old photos taken in the village we live in, outside Saint-Aignan. These were some of the photos we contributed to the mayor's slideshow.


  1. I'm with Starman on the pix!!
    Grey outside, lovely and warm on screen!!!

    As for the challenged...
    weren't most of us taught:
    Far in height = °C x 9/5 + 32
    Centipede = (°F - 32) x 5/9
    It is one of the few things I could do in my head...
    until I got a calculator...
    now I can't!!

  2. I don't think the weather system will come our way. What is occurring is that the cold air in the Arctic Vortex which is normally centered on the north pole is offset, displaced, shifted and deformed. My guess is that it will stay like this for several weeks quite stable, then shift back into its normal position. Horrible if you are under it, weird if you are to the north of it.

  3. Hope you are right, Susan. The weather is notoriously fickle.

    Tim, I used to know those formulas, yes, but now I just use the computer and this site. Also these approximate conversions help a lot:

    –5C —> 25F
    0C —> freezing
    5C —> 40F
    10C —> 50F
    15C —> 60F
    20C —> 70F
    25C —> approaching 80F
    30C —> approaching 90F
    35C —> damn hot
    40C —> 100+F stay inside

  4. C'est parceque les façades orientales des continents sont plus chaudes que les façades continentales à cause de la rotation terrestre. Vous êtes à St Aignan dans un climat tempéré océanique alors que Strasbourg a un climat continental comme en Allemagne par exemple.

  5. Je viens de voir que la température à Urbana, climat continental, est de –24ºC, tandis qu'à Saint-Aignan nous avons +14ºC — presque une canicule, vue la saison.

  6. Beautiful autumn photos, Ken. Perfect for your autumn temps. Ann just posted that it was -15°F in Chicago this morning... up to -10°F right now, and it is -7° F here in St. Louis now.... at 9:30 a.m. Unbelievably cold, and abnormal temps. It hasn't gotten below 0° F in years... down to 0°, but not below it. The last winter that we reached this kind of low was in the late 1980s... and it lasted for much of winter, so I'm afraid we're "in for it" this year.

    Love your conversion chart. Tim's calculations make my head spin, however ( x9/5? x 5/9? really?)

    heh heh :)


  7. To get a "close enough" approximation of the temperature (apologies to Jacques Charles):

    C to F: Multiply the Celsius temperature by 2 and then add 30.

    F to C: Subtract 30 from the Fahrenheit temperature and then divide by 2.

  8. It's 19 in Alabama and pipes will be bursting, plus the poor suffer with inadequate heating.

    Stay warm Judy!

    Love these fall photos.

  9. Ken

    Pour vous une canicule, pour moi 'balmy" in the below zéro low teens :-)


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