The coldest month by some distance, that I've recorded here - 6 years.
The valley location has produced some interesting figures, not just
overnight, but also hanging on to lower temps during the day.
Also very interesting to compare the first 16 days with the next 15.

Mean min -1.1c / 1-16 2.0c / 17-31 -4.4c
Mean max 4.1c / 1-16 6.8c / 17-31 1.3c
Mean 1.5c / 1-16 4.4c / 17-31 -1.6c

18 air frosts.
5 ice days - 18th to 22nd.
15 days snow cover (and counting).

David Mitchell. Langtoft. East Riding.