I’ve spent a bit of time today creating an infographic of driest April’s. I’ve used the free data set maintained by the Met Office, which started in 1910 and is produced from gridded data for ten regions across the country. Hopefully one day the Met Office will extend this series to cover all the rainfall data that they inherited from the British Rainfall Organization in 1919 and just sat on for the last 98 years. I knew about the very anticyclonic and dry April of 1938 from a previous article that I had written earlier this month, but hadn’t realised that it was only driest in three out of the ten regions, even though it was the driest April in the EWP monthly series that started in 1766. The 1.0 mm in East Anglia in 2007 tops the list of driest region by region, which is something else I missed. I’ve borrowed the regional map from the Met Office, I’m sure that they won’t mind, let me know if you spot any issues.
What’s slightly puzzling about these figures for April is why the UK value is the highest April value for all regions at 14.1 mm, when it’s made up of the value for Wales 8.8 mm, and the value for England 6.7 mm. Both values are for the same year 1938, I would have thought that the combined UK value should be some kind of mean of the two, but obviously not. It must have something to do with the gridding I suppose.