December 2016 summary

December was notable for persistent high pressure – the barometer never dropped below 1013.8hPa, which means that the pressure remained above the global average (1013hPa) throughout the month. We recorded our highest December average pressure of 1026.4hPa, and a new record high pressure reading of 1044.3hPa was reached on the 27th.

High pressure often brings calm and dry weather and blue skies, but in winter it may also mean persistent cloud and fog instead of sunshine. All of those features were present during December. Rainfall was 25.4mm, well under half the average and the lowest December total we have recorded; and the wind run came to 889nm which is about one third of our December average, making this our quietest December on record. While we’re talking about records, we also saw our highest December temperature of 15.6C on the 7th December, and our warmest Christmas day (0600-1800) with an average of 12.8C.

That’s an impressive list of new records for one month, but all the other features associated with winter high pressure were present too, even if they aren’t so easily measured. We had clear skies, gloomy days and a fair helping of fog. There were no gales but plenty of calm spells, and there was little in the way of rain with the total on the wettest day (the 15th) only amounting to 8.2mm.

December got off to a cold start, with the thermometer down to -4.9C early on the 1st. There was high pressure across the UK, and fog which formed overnight never cleared during the day: as a consequence the temperature remained below freezing all day, the first time that has happened here since 2010.

We remained under the influence of high pressure, either over the UK or not far away, for almost the whole month – Atlantic lows only made their presence felt from the 12th to the 15th and again around the 21st, and even then we were only on the edge of lows passing to our north. Scotland wasn’t so lucky, with rain and gales there while it was calm here.

Some figures for 2016:-

  • Rainfall total was 606.6mm, a little below average but nothing exceptional
  • The mean temperature for the year was 11.1C, close to normal
  • The highest temperature was 32.4C in July, a new record for this station, and the lowest was an unremarkable -5.9C in January.
  • February saw new records set for wind speed.

That’s a lot of new records for one year, and quite a few of those in December – 2016 will be a hard act to follow.