The UN Climate Change Conference in Paris culminated with international agreement on the need for action. Perhaps that is just as well, as since then weather events around the world have suggested that we are already in an era of previously unknown extremes.

With atmospheric circulation in the Northern Hemisphere more or less locked in the same position, December saw a reprise of November’s themes. High pressure was never far from southern England, so it was the north that bore the brunt of a succession of deep depressions, resulting in flooding that will enter the history books. Our area was spared until the very end.

The first week set the tone: very dull, with temperatures far above normal. Winds were generally moderate from between south and west, bringing a little rain during the evening of December 3, before Storm Desmond arrived to slam into the Lake District on December 6. Its main effect on us was strengthening winds, with a little rain in the night.

Some sunshine on the first three days of the second week relieved the gloom, while clearing skies during the evening of December 9 allowed the temperature in Wellington to fall to 3.0C (37F), our lowest reading of the month. Dull conditions then returned, with some patchy rain at times, before the start of a spell of weather that would be described more than once by professional meteorologists as ‘ridiculous’.

In Wellington, the average temperature for the week commencing December 15 was almost 12C, respectable for the middle of May. It included four days with a maximum of 14C (57F) or more. Putting it in context, in this area there had been only five December days that warm in the last half-century. Although our all-time December daytime maximum was not beaten, a new record was set for our warmest December night. Reports of both roses and daffodils in bloom were fairly common.

Following this heatwave it became very unsettled, with only one rain-free day before the end of the month. Some days were showery with bright spells, and it was quite a bit cooler, though technically still mild for midwinter. Christmas Eve began wet, with sunshine and showers later and a blustery west wind that kept the mercury below 10C (50F) for once. The moonlit night soon dulled over as very mild air arrived for Christmas, giving three more days with a maximum of 14C or more. Wellington’s ten-day old record for the warmest night was broken on December 27, the new figure being an improbable 12.8C (55F).

To the relief of many, December 29 was a mostly sunny day but southerly gales arrived that night in the circulation of Storm Frank. Although the wind slowly eased the next day it became thoroughly wet, giving 26mm (1.02in) in the Wellington rain gauge, our heaviest fall since August. The last day of the year started bright, with showers later, and skies clearing to welcome the New Year with an unfamiliar chill in the air.

While no single extraordinary weather event can be claimed as proof of climate change, many of the statistics for last month leave one stuck for words. It was both duller and warmer than November, itself a record month. December’s mean temperature of 10.5C (51.0F) in Wellington was more than 6C above average, smashing the previous record by an improbably large margin. There were as many notably warm days as in the previous 25 Decembers combined and it was the first December in our records without a single frost. In complete contrast, the rainfall was unremarkable. Although there was rain on 23 days it was rarely heavy, the total of 107mm (4.2in) in Wellington being 94% of the average.

On review, 2015 was quite unusual, with six distinctly dry months. Frustratingly for holidaymakers in the region, July and August were very wet. This may have skewed our perception of the year, which was statistically-speaking on the dry side, the total rainfall in Wellington being 922mm (36.3in). More surprising, perhaps, is the fact that it was one of our warmest years on record, even though we had only two really hot summer days. We’ve forgotten that the first half was very sunny and quite warm, while the cool third quarter was more than offset by the unprecedented warmth we have recently experienced.

Simon Ratsey

(WWN Weather Correspondent