Weather review, December 2010

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  • Weather review, December 2010
    31.12.2010 12:55

     

    The main features of the month were:

    - Exceptionally cold till the 9th, and from 16th-27th

    - Several disruptive snowfalls, notably 1st/2nd, 6th, and 17th/18th

    - Driest, averaged nationally, since 1971

    - Very sunny in parts of Scotland and N Ireland; remarkably dull in the far SE

     

    December 2010 was the coldest December for 120 years and the coldest individual calendar month since February 1986. Snow fell widely and heavily on several days, causing disruption to road, rail and air transport. Worst hit areas were eastern Scotland, northeast England, the north Midlands, and the Home Counties on the 1st/2nd; central Scotland on the 6th; Northern Ireland and Wales on the 17th; and southeast England and the south Midlands on the 18th. There were, however, significant milder interludes between the 10th and 16th, and from the 28th onwards.

    Mean maximum temperature for December ranged from 7.6°C at St Mary's (Isles of Scilly) to minus 0.4°C at Dalwhinnie and Aviemore (both Inverness-shire), while mean minimum temperature varied between 4.9°C at St Mary's and minus 8.4°C at Tyndrum (Stirlingshire). Mean maximum temperatures were between 3.0 and 5.5degC below the average for the standard reference period 1971-2000 in most parts of the UK, while mean minimum temperatures were between 3.5 and 6.5degC below. The Central England Temperature (CET) of –0.6°C was 5.7degC below the long-term mean, and the lowest for December since 1890. The last calendar month with a sub-zero CET was February 1986.

    The highest maximum at a standard site (i.e excluding rooftop and mountain sites) in the UK was 11.5°C at St Mary's (Isles of Scilly) on the 28th, while the lowest minimum was minus 21.1°C at Altnaharra (Sutherland) early on the 1st. The were ten individual nights during the month when the temperature dropped below minus 18°C somewhere in the UK. The lowest daytime maximum was minus 15.8°C on the 22nd also at Altnaharra, and the warmest night was that of the 27th/28th with a minimum of 10.5°C at St Mary's.

    Rainfall averaged over England and Wales (including a small estimated figure for the 31st) was 39.5mm which is 39 per cent of the average for the standard reference period 1971-2000, and the lowest for December since 1971;  in the last 100 years only five Decembers were drier while 95 were wetter. The equivalent figures for Scotland were 48mm and 47 per cent of the normal amount, and for Northern Ireland 59mm and 60 per cent. Monthly totals at routinely-available sites ranged from 117mm at  Guernsey airport (Channel Is) to just 7mm at Shap (Cumbria).

    Sunshine averaged over England and Wales (including a small estimated figure for the 31st) during December was 56 hours which is 117 per cent of the 1971-2000 mean.  The equivalent figures for Scotland were 59 hours and 178 per cent, and for Northern Ireland 80 hours and 227 per cent.  Largest total was 92 hours at Auchincruive (Ayrshire), and the smallest was just 10 hours at Charlwood (Surrey).

    It was a remarkably quiet December with no widespread gales. The windiest day of the month was the 16th with gusts to 56kn (65mph) at Capel Curig in Snowdonia.

     

    Regional Breakdown

     

    Difference from the average (1971-2000)

    Mean Max

    (deg C)

    Mean Min

    (deg C)

    Rainfall

    (per cent)

    Sunshine

    (per cent)

     

     

     

     

     

    Scotland (Highlands and Islands)

    –3.9

    –4.7

    42

    186

     

     

     

     

     

    Scotland - Central Belt and east coast

    –5.0

    –5.8

    52

    170

     

     

     

     

     

    Northeast England

    –5.1

    –6.3

    57

    169

     

     

     

     

     

    East Anglia

    –4.9

    –4.9

    36

    109

     

     

     

     

     

    Midlands

    –5.3

    –5.7

    34

    103

     

     

     

     

     

    Southeast England

    –4.9

    –4.6

    49

    67

     

     

     

     

     

    Northwest England and North Wales

    –4.3

    –6.3

    35

    165

     

     

     

     

     

    Southwest England and South Wales

    –4.6

    –5.7

    31

    122

     

     

     

     

     

    Northern Ireland

    –5.0

    –5.1

    60

    228

     

     

     

     

     

    IrishRepublic

    –5.2

    –4.5

    57

    162

     

     

     

     

     

     

    © Philip Eden 101231