As in a big part of the country, it's been REALLY cold the last week or so. Yesterday was the coldest day in Des Moines, IA and will probably be the coldest day of the year.
low -18F high -3F
Here are a couple of blocks to give you a picture of how c-c-c-o-l-d it's been.
I know for a fact that the coldest temperature for "yesterday" happened after midnight on the 16th (today).
So just to complicate things a little more, I did some research this morning and found this on a local station's page:
"On this weather page... daily high and low temperatures appear in chronological order. ...the high that appears here is our forecast for the maximum temperature expected that... afternoon; the low is for the lowest reading during in the evening or the next morning.
Similarly for all other days. National Weather Service forecasts follow an identical format.
However, for climatological purposes, daily highs and lows are defined (by international convention) as the maximum and minimum temperatures that occur during the midnight-to-midnight period, local standard time, regardless of the time of day those extremes might occur."
This means that now we have to decide whether to use National Weather Service data or climatological data.
I think the best thing is to be consistent.