The last half of January is the coldest part of winter, with the worst weather. I’m in central Indiana.
I voted December, because even though January would seem like it should be colder, December always feels colder.
I went and looked it up and, historically, December is ever so slightly (1 degree) colder.
So, go me!
In my anecdotal opinion, here in Chicago, January and February seem to be pretty much tied for worst weather months of the year. I’ll give January a slight edge for the absolute worst, but only because it is a few days longer than February.
According to Raleigh(RDU) Daily Normals in these here parts the coldest days on average are January 7th through the 10th.
South West England, and here’s it’s February, by a whisker.
Average highs 7C (45F), lows 3C(37F). It’s a fair bit milder than that currently.
January, without a doubt.
“As the days grow longer, the cold gets stronger.”
I vote for February.
No “All of the above” option for Canadians? 
Those of us with outdoor rinks know exactly when the coldest snaps are!
It’s definitely January here, but December is the most miserable. It’s dark, wet, cold, and sometimes frigid.
According to official weather records, January is the coldest month here in Southern Maine. The minimum of the average daily temperature curve occurs about January 20. February is 2.5 degrees Fahrenheit warmer than January, but somehow it seems colder.
October is the “coldest” month of the year here in Panama (daily high/low 85/76 F), but that’s because it’s the depths of the rainy season. The hottest month is April (90/78 F), at the end of the dry season.
Yes, the CET (Central England Temperature, an average figure for roughly the English Midlands) is at its lowest in February: 3.7C on average, compared with 4.7C in December and 3.9C in January. That’s a daily average figure, taking the mean of the maximum and minimum. Daytime highs are normally about 7-8C, lows around freezing.
In recent years we’ve tended to get winter quite late, with cold spells and snow in late February and even into the second half of March. At the moment it’s in double figures (Celsius) in southern England.
New England: Massachusetts. January always feels the coldest to me and I believe it is. However, there are “warm January” years and (literally) brutal Februarys (sp?). As a child it felt like winter came in December, which is literally when Winter begins. Yet as I think about (and experience) the changing temps the cold settles in slowly around here, while the warm weather seems to come, well, in buckets (as in faster). For the record, since semi-retirement, which is several years now, I’ve been wearing shorts as long as possible. I aim for six months, which is tough, though five months is easy. That’s half or damn near half the year, which, when I started doing this, truly surprised me.
usually February around here. But the freakish weather we have been getting this year, who knows what February will bring aside from that fool groundhog!
This is my first winter in Edmonton, AB.
My understanding is that February is the coldest month… but this morning, I woke up to a temperature of -38 F. I am, clearly, not prepared at all for February.
Here’s the update from my corner of south Texas. So far this month has been very warm. This week the afternoon highs have been around 80 and the morning lows around the high 60s. The weather people on the local news are using the heat index rather than the wind chill. It’s going to cool down a little this weekend, but this month will almost certainly be warmer than both last November and December. Even the latter part of last October will likely end up having been cooler than January.