UK Lookback - January 01, 2015
December 2014 Lookback
Notably mild 16th-24th; colder after with severe frosts

By Philip Eden

The pressure for December 2014 was 4mbar below normal in Shetland but 7mbar above in south-west Ireland. The anomalous flow over the British Isles was west to north-westerly. All parts of the country had near normal temperatures (slightly below average in Scotland) but there was a notably mild spell from the 16th to the 24th after which it turned much colder with frequent severe frosts. Scotland and Northern Ireland were rather wet but much of England and Wales was dry with rainfall percentages ranging from 155 in the Highlands and Islands to 66 in south-west England and south Wales. Sunshine percentages ranged from 86 in north-west England and north Wales to 165 in the English Midlands.

Mean maximum temperature during December ranged from 4.1°C at Braemar (Aberdeenshire) and Braemar (Aberdeenshire) to 10.6°C at St Mary's (Isles of Scilly), while mean minimum temperature varied between minus 1.8°C at Cromdale (Morayshire) and 8.4°C at St Mary's (Isles of Scilly). Mean temperatures were between 0.5 and 1.0degC below average in Scotland and Northern Ireland but 0.0 to 0.5degC above the long-term average over England and Wales. The Central England Temperature (CET) of 5.3°C was just 0.6degC above the mean for 1981-2010; this was the coldest December only since 2012, but in the last 100 years 53 Decembers were colder, four had the same mean temperature, while 43 were warmer.

The highest maximum at a standard site (i.e excluding rooftop and mountain sites) in the UK was 14.2°C at Nantwich (Cheshire) on both the 17th and the 22nd, while the lowest minimum was minus 9.0°C at Cromdale (Morayshire) on the 27th. The lowest daytime maximum was minus 3.2°C at Cromdale (Morayshire) on the 26th, while the warmest night occurred during the early hours of the 22nd with a high minimum for December of 12.7°C at Linton-on-Ouse (North Yorkshire) on the 22nd.

Rainfall averaged over England and Wales during December in a record stretching back to 1766 was 77.5mm which is 80 per cent of the average for the standard reference period 1981-2010; this was the lowest December rainfall since 2010; in the last 100 years 32 Decembers were wetter while 68 were drier. The equivalent figures for Scotland were 136.1mm and 132 per cent of the normal amount, and for Northern Ireland 105.5mm and 110 per cent. Monthly totals at routinely-available sites ranged from the large total of 554.8mm at Achnagart (Wester Ross) to 20.8mm at Inverbervie (Kincardineshire). The heaviest daily fall was 78.8mm on the 21st at Tyndrum (Stirlingshire).

Sunshine averaged over England and Wales during December was 79.7 hours which is 152 per cent of the 1981-2010 mean, making this the sunniest December since 2001, and in the last 100 years only one December was sunnier while 99 were duller. The equivalent figures for Scotland were 45.1 hours and 116 per cent, and for Northern Ireland 55.7 hours and 128 per cent. Largest total in the UK was 101.5 hours at Durham (Co Durham), and the smallest was 13.2 hours at Lerwick (Shetland).

Strongest winds during December occurred on the 10th with gusts to at both 81mph at South Uist (Western Isles) and Tiree (Inner Hebrides).

By Philip Eden

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