January, 1947: Unsettled;large temperature variations;snow and intense frost late in month
The month was noteworthy for the frequency of gales from the 1st to the 17th, a very mild spell at the beginning of the 3rd week, followed by a severe wintry spell when some very low temperatures were recorded.
On the 17th, an anticyclone to the south-west of the British Isles developed, drifted slowly east and then north. From the 20th until the end of the month pressure remained highest to the north and north-east and there was a gradual change, first felt in east and south-east and south-east England, and later over the whole country, to unsettled weather with frost and snow and easterly winds. Continuous frost set in over south-east England on the 23rd, over Wales and western England on the 28th, and over Scotland on the 29th. Depressions and their associated troughs to the south of the British Isles from the 25th onwards brought snow at first to south-east and east England, and later everywhere.
Pressure and Wind: Mean pressure for the month exceeded the average in the north and was below it in the south and south-west. The departure from the mean at 9h. varied from +7.6mb. at Lerwick to -5.7mb. at Plymouth. South-westerly winds were prevelant between the 1st and 3rd and from the 8th to the 17th, south-easterly winds from the 4th to the 7th, and easterly winds from the 20th to the 31st. Among the highest speeds recorded in gusts were 74mph at Lerwick on the 3rd, 79mph at Pendennis Castle, and 68mph at Boscombe Down on the 13th, and 74mph at Bell Rock on the 15th.
Temperature:Mean temperature for the month was below the average everywhere, the deviation from the monthly average ranging from -1.5°F (-0.8°C) in east Scotland to -4.5°F (2.5°C) in east England.The coldest week was that beginning on the 26th when the departure from the weekly average was -11.6°F (6.5°C) in England and Wales, and -6.5°F (-3.6°C) in Scotland. Day maxima at or below 32°F (0.0°C) appeared on the 25th in in east and south-east England. Thereafter, continuous frost gradually became more intense and the area covered by it more extensive so that by the end of the month there was continuous frost almost everywhere in the British Isles. On the 29th and 30th the cold was most severe. Maxima below 30°F (-1.1°C) were common as were minima below 10°F (-12.2°C). On the 29th the maximum was 21°F (-6.1°C) at Little Rissington, 29°F (-1.7°C) at Newquay and 28°F (-2.2°C) at Scilly.
The extremes for the month were (England and Wales) 57°F (13.8°C) at many inland places on the 16th, -5°F (-20.6°C) at Writtle (Essex) on the 30th; (Scotland) 56°F (13.3°C) at Prestwick on the 15th, 8°F (-13.3°C) at Kelso on the 31st; (Northrn Ireland) 54°F (at a number of places on the 14th and 15th, 18°F (-7.8°C) at Aldergrove on the 30th,
Precipitation:The general precipitation, expresses as a percentage of the 1881-1915 average, was 113% over England and Wales, 115% over Scotland, and 103% over Northern Ireland.
Snow occurred in south-eastern districts of England from the 23rd until the end of the month. The snowfall of the 28th and 29th was widespread and even affected the extreme south-west of England. On the 30th snow lay to a depth of 7 inches (18cm) at both Scilly and the Lizard
Sunshine:There was a marked contrast in the amounts of sunshine between the northern and other districts of Scotland. Sunshine amounted to 123% of the the average in the north but to only 86% in the southern districts of Scotland. Sunshine exceeded the average by more than 20% in east and south-east England but was below average in Wales and elsewhere in England
Miscellaneous Phenomena:The aurora was observed in Scotland on 9 nights. Solat halos were noted at Oxford on 6 days.