More December temperature records

As the north of England struggles with prolonged rainfall and catastrophic flooding, down here the December temperature records just keep on falling. Yesterday saw a new record daytime (0600-1800) average of 14.2C: and, if that wasn’t enough, Christmas night (1800/25th to 0600/26th) saw exactly the same average, beating the overnight record set only a few days ago.

The average so far this December is now 11.3C, about 6C above what we would expect for December and still warmer than the record-breaking November.

As I’m typing this I see the thermometer is at 14.5C and rising. I wonder if we might see a new maximum temperature too – the current record is 15.4C early on the 20th. Watch this space.*

(*) Update 1900 – no new maximum temperature record today, but we came close with 15.3C at 1355. More exceptionally mild weather is forecast before the end of the month, though, so it could still happen.

And warmer still . . .

Yesterday’s record December temperature of 15.1C has been beaten already – just after midnight, thanks to warm air streaming up from the southwest, the thermometer here reached a new December high of 15.4C.

The average overnight temperature (1800-0600) hit 13.9C again, despite some clear spells, and this month’s average temperature now stands at 11.5C: warmer than November, and approaching October’s average of 11.8C.

Warmest December night

There has been some talk in the media today about the exceptional warmth last night, and the figures for this weather station are no exception – last night’s average for 1800-0600 was 13.9C, by far the warmest December night we have recorded since the station was set up in 2007. To underline how very mild this December has been, seven of the top 10 warmest December days and nights recorded here have occurred during this month.

The average temperature so far this month is now 11.4C: that’s an increase of 0.3C on the average up to three days ago, and 0.4C warmer than the average for the whole of last month (which was our warmest November on record). A normal figure for this point in December would be 5.1C, and the previous record-holder for the same period was 2013 with 7.4C – so this December so far is 4C warmer than 2013, and the gap is widening.

One other point – at 0736 today we recorded a temperature of 15.1C, a new record high for December.

Needless to say there have been no air frosts this month, and from the forecasts it looks as if we could be heading for a frost-free December. Meanwhile, the hedge is still growing . . .

 

 

 

 

Record-breaking December mildness

The mild weather that we experienced in November is still with us, and the mean temperature so far this month is 11.1C.
This station’s average for the first half of December in previous years is 5.2C, ranging from 1.3C for the first half of
Decemer 2010 to 7.5C in 2013. The current extraordinarily mild spell follows the warmest November we have recorded since the station was set up in 2007.

At this point in December we would normally have seen several air frosts: on average the thermometer here has dipped below zero on five or six occasions by the 16th. There had been 11 air frosts at this point in December 2010, but only one in 2011. In the first half of December this year the lowest temperature we have seen is 2.3C – there have been no air frosts at all.

As with November, the cause of this mildness is a persistent air flow from the south Atlantic: a conveyer belt of warm, wet air. Satellite images taken during the devastating rainfall in Cumbria from the low pressure system “Desmond” showed a line of cloud stretching right back to the Bahamas, and as this warm, humid air rose over the Lake District Fells it deposited rain for hour after hour. The rainfall total here so far this month is a modest 18.6mm, and apart from the unseasonal temperatures the main effect of the air stream has been a blanket of cloud – it has been unrelentingly dull and gloomy.

Forecasters are predicting even milder weather for the coming few days so we may see that December temperature average climb higher still. Gardeners will know that we need hard frosts in the winter to kill the pests and allow plants to become dormant and get some rest: I can tell you that the hedges and grass here are still growing.

November 2015 summary

November was unusually mild and windy, but not particularly wet. Low pressure systems were the dominant feature, but for much of the month there was a persistent high pressure area over Europe and, as the Atlantic lows moved along the northern edge of this high pressure, warm and humid air was channelled over the south of the UK – hence we saw a good deal of mild and cloudy weather.

November began with very quiet weather – almost a dead calm – and for the first couple of days low ground was covered in a blanket of fog while hilltops were bathed in sunshine. A temperature of 22.3C was recorded at Trawsgoed in Wales on the 1st, a new UK record for November, but here in the fog we could only manage 12.2C. The 6th produced a new November temperature record for this station, reaching 17.7C at lunchtime in cloudy conditions – a good indicator of the warmth of the south-westerly airstream. The arrival of the first low pressure system to be named by the Met Office, Abigail, on 12th November put an end to the quiet spell, and was soon followed by Barney which produced the highest wind speeds of the month – an average of 27kts gusting to 36kts was recorded on the evening of the 17th.

The only chilly spell was from the 20th-24th, when the high over Europe receded and Atlantic lows pulled cold Polar air over the UK, producing the only air frost of the month early on the 23rd. At least we saw some blue skies in the cold, clear air.

The end of the month saw another area of high pressure develop to our south and a deep low pressure system (Clodagh) to the north. This meant a return to milder weather, but also brought more wind and rain – alhough wind speeds were not quite as high as they were in the middle of the month, the wind was persistent. Overall, this was the second-windiest November recorded here.

It was also the warmest November we have recorded with an average of 11C, as well as that high of 17.7C. The rainfall total of 67.4mm, though, was a little below average.

Despite the mild November, overall autumn temperatures were about average at 12C – September and October were both fairly cool months and offset the mild November. Rainfall was below average, though not exceptional, at 150.6mm.

———

Updated 2 Dec 2015 to correct the date of the record high temperature of 17.7C.