The unsettled weather continued on Monday with much more rain, 16.0mm to start the new month, thanks to an extensive rain band that at times reached from Cornwallto Essex. However, it was very mild again thanks to the southerly airstream for much of the day gusting to 27mph. A maximum of 11.5C was 4.4C above the 39-year average and a low of 10.1C early Wednesday was 9.9C above the long-term average.
The new day on Tuesday was even darker than previous days with very thick, low cloud and yet again rain falling that triggered the automatic rain gauge at 06.15.
There are four depressions circling the UK, one of which is heading for central England around mid-day. The pressure reading at 08.00 was 987.5mb and falling rapidly. Rain will fall until well after midday and the wind is likely to strengthen as the morning progresses.
December 2023 Review
The first two days felt more like the beginning of winter with both maxima and minima well below the 39-year average. The maximum on the 1st of 0.7C being 7.2C below average and a hard frost during the night of the 2nd when the thermometer dropped to -4.1C around dawn on the 3rd.
All changed on the 3rd with a very wet and dull day when rainfall of 18.0mm was recorded.
The unsettled weather continued with Storm Elin arriving on the 9th bringing much rain, another 18.1mm and strong wind, gusting to 33mph. Then Storm Fergus came hot on its heels the following day producing more rain. Both storms were named by Met Éireann as it impacted principally Ireland.
During that weekend the very warm and moist air pushed the temperature to 12.3C being 4.3C above average, likewise the following night was very mild when the thermometer did not drop below 7.3C, which was 5.0C above the long-term average.
An anticyclone arrived just to the west of the UK that pushed a ridge of high pressure over the UK on the 15th that started a period of warmer air and cessation of rain. The barometric pressure rose to a very high value of 1040.8mb on the 16th, not seen since February 2023. The mild air brought several days of mild weather and a very mild night 16th/17th with a low of 8.6C being 6.3C above my 39-year average. The diurnal variation, difference between day and night, was just 2.0C between day and night.
Storm Pia, named by the Danish Meteorological Institute, passed to the north of our area on the 21st, but it did result in a windy day, with a peak gust of 37mph. The very mild weather continued with the thermometer on that day peaking at 12.9C, some 5C above the average. Very little warmth was lost overnight resulting in a very mild night when the thermometer did not drop below 9.4C, some 7.3C above my 39-year average.
After a lull over Christmas with very mild conditions, another storm, Storm Gerrit named by the Meteorological Office, arrived on the 27th bringing more rain and strong winds.
However, the end of the month had a sting in its tail. A very deep depression, with a central pressure of 967mb, travelled from the Atlantic across Ireland that produced the wettest day in two months with a twenty-four-hour total of 24.3mm. The lowest barometric pressure, also in two months, was 985.5mb early on the 31st when another 12.2mm of precipitation was recorded.
The figures show just how warm the month has been with the mean temperature a significant 2.5C above my 39-year average. It was the warmest December since the record was set in 2015. There were only three days when an air frost was recorded, the long-term average is 10.5. The analysis shows that the mean daytime temperature was +2.2C, only six maxima were below the mean temperature. The mean night-time temperature was +2.8C, only five nights were below the mean.
The total rainfall for December was 142.8mm being 154% of my 39-year average or plus 50.1mm. This is not a record as in 2013 a record 157.0mm fell in December of that year.
Due to the frequent depressions passing our way it was not only a wet month but a dull month with the global sunshine logging just 25 hours when the long-term average is 51.
Another interesting fact is that the diurnal range of temperatures, the difference between day and night, has shown an increasing range. It was approximately 11C in the 1980’s and has now widened to an average of 13.7C in the last few years.
Year 2023
The mean annual temperature has seen a very clear, steady rise since the early 1990’s, increasing from approximately 8.9C to 9.8C over the last few years. The year 2023 was 0.8C above my 39-year average. Do check out the data and graph on the website using the ‘Mean Temperatures’ tab then Annual Temperature’.
The rainfall for the twelve months amounted to 1150mm making it a record for this station set up 39 years ago in 1984. The previous high was 1146mm in 2002. Warmer air holds more moisture, so it is not surprising to find that over the period since 1984 the average annual rainfall has risen from approximately from 815m to 850mm over the five years.