Spring-like weather in winter...

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  • Spring-like weather in winter...
    03.03.2011 15:55

     

    There are often arguments as to which dates define the winter season in the northern hemisphere, with some advocates for the period between December 21  and March 20 – the solstice to the equinox.

    Meteorologically, though, winter runs through the calendar months of December, January and February, which are on average the three coldest months of the year.

    Notwithstanding the current chilliness, we have now embarked on a journey through spring, although temperatures have dropped since the balminess of a couple of days in late February. The weather is no respecter of the calendar.

    There is no question, though, that December fulfilled its wintry remit, given its snowiness and the frigid temperatures that made it the coldest December for 120 years.

    After such a start we might have been looking at further record-breaking temperatures for the winter as a whole - but it is unusual for the weather to get locked into a pattern for as long as three months and the harsh conditions duly receded. The extraordinary winter of 1946 to 1947 was one exception, with cold and snow from late December to the middle of March.

    February 1947 was the coldest month of that winter, with a Central England Temperature (CET) of -1.9 degrees Celsius, about six degrees below average and still the coldest February on record. December 2010 was comparable although not record-breaking, with a CET of -0.6 degrees Celsius, 5.7 degrees below normal.

    In a way we have had a kind of “winter in reverse”. January’s CET was only half a degree below average at 3.7 Celsius, although Scotland was notably colder. February was of course much milder on average, with a CET of about 6.6 degrees Celsius, which is 2.4 degrees above normal. The highest February CET on record was 7.9 Celsius in 1779.

    February 2011 was the ninth warmest since 1910 and in the top 20 warmest since 1659, which helped to make the winter as a whole less cold than the previous winter and only the 15th coldest in the last 100 years.

    It used to be very unusual for December to be colder than February. Whether some recent winters mean that there is a trend to the opposite awaits many more years’ evidence.

    By: Stephen Davenport