When Is Winter?

I mean, c'mon when is it ever going to be spring? This snow and cold is getting to be a bit much! Time to be riding on the road, right?

Well, actually, this weather is basically pretty normal.

There's so much cultural run-up from Thanksgiving to Christmas and New Years that we tend to think of the end of our winter holidays as the mid point of the winter. In fact, Christmas is actually only a couple days after the winter solstice. So from a daylight standpoint, yes, we do have bright holidays to distract us at the darkest time of year. But officially, the solstice is just the first day of winter. In fact, that's how it plays out from a temperature standpoint too.

When designing and operating systems for heating buildings we speak in terms of "heating degree days". They help us quantify: "how cold was it this winter compared to last winter?" and quantify and compare the energy use of a building in a winter that had a few really cold days to the same building in a winter that had a lot of average-cold days.

Heating degree days are defined relative to a base temperature—the outside temperature above which a building needs no heating. Typically, we'll use 65°F outdoors as the temperature above which buildings need no heating, since there are usually things in the building that provide a little heat such as people, lighting, washing, and cooking.

So if the outdoor temperature averaged 25°F yesterday, we accumulated (65-25) = 40 degree days.  A typical winter in this area might have 5000 degree-days.

Based on monthly records for the past thirteen winters, what we find is that January is the coldest month followed by February. December is third coldest on average, then March. Of course there's lots of variation. But the point is: like it or not, this is what February in NJ looks like.

More miles in the basement!