When T.S. Eliot wrote “April is the cruellest month”, he was probably not discussing our climate. Even so, with spring so far advanced this year, it was a shock to be de-icing the windscreen before the morning commute, in April. That said, the long-term averages indicate that spring warming reaches a temporary peak at the end of March followed by a sharp relapse. Significant recovery then doesn’t occur until the second half of April, as was to happen this year.

April 1 fooled us with unbroken sunshine and a temperature in Wellington of 16C (61F), the rest of the first week being pretty grim. With a weak jet stream crossing Britain from the north, a depression formed in cold air over the North Sea and drifted slowly south into Europe. There were hail showers on April 2, followed by a frosty night, a brisk north-westerly the next day keeping Wellington’s maximum to just 9C (48F), making it our coldest day for four weeks. April 4 saw spells of rain that became heavy in the night, giving the month’s heaviest fall of 26 mm (1.02 ins), with more rain the following day.

April 7 saw the start of a brief improvement, as high air pressure formed over Scandinavia. This trend was quickly reversed as the anticyclone then drew air from a source in the Russian Arctic across us, giving a short string of frosty nights. A minimum of -1.6C (29.1F) in Wellington first thing on April 11 was one of our lowest temperatures since early February, followed by a cool day with uninterrupted intense sunshine.

Halfway through the month, and we’d had more frosts and fewer warm days than in the second half of February. A static weather front over us on April 15 gave a wet day, but marked the beginning of a spell with winds reaching us from a southerly quarter. A rapid warming saw 18C (64F) in Wellington on April 17, the year’s highest temperature thus far. Over the next four days, there was sunshine in abundance and progressively higher temperatures. This conveniently coincided with Easter, a maximum of 23.4C (74.1F) on April 21 being slightly lower than the reading on the same date last year, but giving us our hottest Easter Day on record. With air that originated over North Africa, it was no surprise that we had light falls of Sahara dust on a couple of nights.

The last of the hot days was April 23, ending a six-day spell with maxima in Wellington of 21C (70F) or more on each day - an all-time record for the month. Six of the ten hottest April days on record have occurred in the present decade. Things then became cooler and more unsettled, Storm Hannah arriving during the night of April 26/27 to give unusually strong winds for the time of year, shredding new leaves and stripping them from the trees in quantity. But the month ended pleasantly warm and sunny.

In spite of the distinctly chilly first half, April’s mean temperature of 9.7C (49.5F) was over a degree above the long-term average, but fairly normal for the present century. The total rainfall of 79mm (3.1ins) was 127 per cent of the average, with sunshine amounts close to average.

Simon Ratsey

(WWN weather correspondent)