April 2017 summary

April was the driest month since we started recording here in September 2007, with a rainfall total of just 11.8mm. The previous record holder was May 2010 with 12.4mm.

Records on this site start the weather day at midnight, but traditional Met Office rain gauges are usually read at 0900 (so observers don’t have to scrabble around in the dark) and this means that any rain falling between midnight and 0900 “belongs” to the previous day. Normally this makes little difference over a month, but this morning we recorded 10.0mm of rain between midnight and 0900. If we were using the traditional Met Office weather day, starting an 0900, April’s rain total would almost double to 19.4mm (not 21.8mm, because 2.4mm of April’s rain would belong to March). It would also mean April would have been the 8th-driest month we have recorded, and not a new record holder. All this tells us is that Mother Nature is no respecter of calendars, clocks or statistics.

Rain fell on seven days during the month, and only three of those exceeded 1.0mm. The dry weather was a consequence of persistent high pressure which kept Atlantic lows at bay for most of the month, and brought some welcome sunshine too.

It wasn’t all plain sailing – there were some dull spells when cloud was trapped under the high pressure, and lows did put in an appearance on the 1st, the 25th and of course right at the end of the month on the 30th – hence all that overnight rain. We managed a respectable maximum temperature of 21.1C at lunchtime on the 9th only to see the thermometer plunge during the aftenoon as we switched to cool polar air: a feature which also took the edge off temperatures later in the month, and produced just a few April showers as cold air met warm.

Despite the clear skies there were no hard frosts, with a minimum of 0.0C recorded early on the 27th. The average temperature for April was 9.8C, about normal for this time of year.

Updated 2000 1 May 2017: after a couple of convective showers this afternoon (and some distant thunder), today’s rainfall total has reached 11.8mm. That’s nothing exceptional, but it does mean we have recorded as much rain today as we did in the whole of April.