Exceptional early and late cold spells

[hillbilly]

Looking at the lists of exceptional cold temperatures over the extended winter  figures of -20 deg are fairly evenly spread from 30th November to 8th March.Out of this period are two days  12th March [-22.2deg] and 14th [-22.8 deg] which seem a little cold in comparison and fit in better had they been 2 or 3 weeks earlier.At the earlier end of the extended winter there is an even bigger anomaly,that of 14th November[-23.3] and 15th[-22.8 deg]. buth amazingly cold for that time of year and nothing colder until December 3rd.Is there any reason for these out of place temperatures or do we just put it down to statistics?

[damianslaw]

5 minutes ago, hillbilly said:

Looking at the lists of exceptional cold temperatures over the extended winter  figures of -20 deg are fairly evenly spread from 30th November to 8th March.Out of this period are two days  12th March [-22.2deg] and 14th [-22.8 deg] which seem a little cold in comparison and fit in better had they been 2 or 3 weeks earlier.At the earlier end of the extended winter there is an even bigger anomaly,that of 14th November[-23.3] and 15th[-22.8 deg]. buth amazingly cold for that time of year and nothing colder until December 3rd.Is there any reason for these out of place temperatures or do we just put it down to statistics?

I suspect those mins were in the Highlands and occured over deep snow cover, light winds, and an arctic airstream. Northerly airstreams are quite common in March so not too surprised about those stats for March. However, the November ones are notable, the ground still has alot of summer heat within it, and arctic airstreams don't pack as much a punch, but perhaps on those occasions the summer and autumn had been very cold over the arctic to enable such low temps.