The high pressure now centred over the UK has been intensifying over the past twenty-four hours, as a result it has blocked the flow of Arctic Air but left a pool of very cold, static air over the UK. The thermometer on Monday, during 6.7 hours of sunshine, rose to a maximum of 9.7C, however, this was again below average (-4.3C).
The thermometer fell steadily downwards during Monday evening and at 22.39 dropped below freezing (-0.1C), just six minutes later than the previous night. The past night has been the coldest since 11th February win a minimum of -3.9C at 06.20 on Tuesday morning being a significant 8C below average. In fact we have only had one day and night with temperatures above average.
Tuesday saw bright, if muted sunshine for the first hour but a fog bank, which had been lurking to the north of Marlborough from the Thames Valley, rolled in over the Downs so that by 07.15 the visibility had reduced to 200m. The sun disappeared half an hour later so that by 08.00 the temperature was still below freezing with a reading of -0.4C.
The anticyclone has dampened out the wind of previous days and dropped out entirely for many hours overnight thus allowing the frost to intensify. The barometric pressure at 08.00 was 1033.7mb