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View Full Version : Why is the middle of winter the coldest?

snailboy
03-09-2009, 09:28 PM
Winter solstice, the shortest day in a hemisphere, is at the beginning of winter in late December. Since that's when there's the least sunlight, that's when you'd expect the coldest days. Yet January and early February tend to be colder. Why is this? Does it simply take a while for Earth's temperature to catch up with the amount of sunlight it's receiving due to its heat capacity?

IdahoMauleMan
03-09-2009, 09:33 PM
Winter solstice, the shortest day in a hemisphere, is at the beginning of winter in late December. Since that's when there's the least sunlight, that's when you'd expect the coldest days. Yet January and early February tend to be colder. Why is this? Does it simply take a while for Earth's temperature to catch up with the amount of sunlight it's receiving due to its heat capacity?

Yes.

snailboy
03-09-2009, 09:44 PM
10-4. That was a quick and easy answer. I'm going to have to start coming up with harder questions.

Chronos
03-09-2009, 09:50 PM
Which is basically the same answer as to the question we had the other day about it getting colder at dawn.

bobot
03-10-2009, 02:47 AM
Since the original question has been answered...hijack.
If the daily teperatures were charted, beginning of winter to the end, would they form a bell curve?

CookingWithGas
03-10-2009, 07:41 AM
If the daily teperatures were charted, beginning of winter to the end, would they form a bell curve?The term "bell curve" means something pretty specific in statistics with regard to frequency distribution. That's not the same thing as charting temperatures over time. My guess (I couldn't find any actual data after a few minutes of searching) would be that a chart of temperatures would be close to a sine curve, which is roughly similar to a bell curve but not mathematically the same.

K364
03-10-2009, 07:42 AM
So, when is the middle of winter?

Second week of January?

CookingWithGas
03-10-2009, 07:52 AM
So, when is the middle of winter?

Second week of January?In the northern hemisphere the middle of winter is around Feb 5. Halfway between 12/21 and 3/20.

friedo
03-10-2009, 11:06 AM
It's also worth noting that the identification of the solstices with the beginning of seasons seems to be a uniquely North American phenomenon (http://www.straightdope.com/columns/read/161/is-it-true-summer-in-ireland-starts-may-1).

So it depends on your definition of "middle." :)

A Dodgy Dude
03-10-2009, 03:37 PM
I don't know if this helps the conversation any, but here goes:

In NYC, the absolute dead of winter is January 21-25. On those five days, the average temp is the lowest it gets for the entire year ... 31.5 degrees as I recall.

Annie-Xmas
03-10-2009, 03:42 PM
As the days lengthen
The cold does strengthen

The days grow longer
The cold grows stronger

Both Old New England sayings

snailboy
03-10-2009, 03:49 PM
It's also worth noting that the identification of the solstices with the beginning of seasons seems to be a uniquely North American phenomenon (http://www.straightdope.com/columns/read/161/is-it-true-summer-in-ireland-starts-may-1).

So it depends on your definition of "middle." :)

Very interesting.

Polycarp
03-10-2009, 03:57 PM
In the northern hemisphere the middle of winter is around Feb 5. Halfway between 12/21 and 3/20.

The old "cross-quarter days" beloved of Neopagans were originally the halfway points through the seasons: Imbolg (Candlemas, Groundhog Day) - Feb. 2; Samhain (All Saints, Hallowe'en) - Oct. 31-Nov. 1; May Day, May 1; and Lammas, in early August.

K364
03-10-2009, 10:35 PM
In the northern hemisphere the middle of winter is around Feb 5. Halfway between 12/21 and 3/20.
To clarify what I meant was...

Statistically, when is the cold of winter likely to bottom out? As A Dodgy Dude explained for NYC. Likely to vary a bit by region I guess.