I’ve just noticed that there seems to be a disproportionate number of cold last weeks of February and first week in March in the daily CET records (fig 1). Only someone as crazy as me would be writing code on a lovely sunny Sunday with Mediterranean blue skies outside to discover this trivial and useless nugget of information regarding temperatures in central England since the millennium. Statistically six out of the last 245 years in the top 30 is probably no more or less than what you would expect, but in recent years there have been so few examples of any month that was colder than average (apart from 2010) that it came as a bit of a surprise to me. These colder inter month periods have probably gone unnoticed because you often view climate periods on a calendar month basis, or at least I do.
Anyway the original reason why I started doing this little spot of research was to find out just what were the coldest end of February start of March periods since 1772. I could then gauge statistically just how cold the next couple of weeks of cold had been in the series.
The upshot of that work confirmed what I already thought might be the result, and that is that this coming cold spell of very cold weather is going to have been pretty spectacular if it’s to equal or surpass the exceptional same period in 1947 (fig 2).
According to results that I’ve generated, the mean temperature for the period 21st February to the 7th of March was -2.2°C, that ‘s -6.6°C below the long-term average (1961-1990). That’s a clear 1.4°C colder than 1786 the next coldest such like period. Even if we do have a couple of ice days in this coming week in central England I can’t see how the mean temperature can get anywhere near that of 1947, although it might push the means for 2005 and 2006.
This period has shown only a very slight warming over the years of just 0.006°/decade, which equates to a small warming of 0.15°C in the last 245 years (fig 3). Perhaps this is the last vestige of how the temperatures were during the late 18th and 19th centuries in central England, now that’s another crazy thought.