May 1896 most anticyclonic
Looking at the Jenkinson Lamb objective weather data from the CRU at the UEA, I find that May 1896 was the most anticyclonic across the British isles in the record that started in 1871. I’ve gauged this on the combined frequency of the daily anticyclonic or hybrid anticyclonic LWT. May 1896 scores an extremely high 74% anticyclonic for the whole month, which is way ahead of the next year in the list, 1871 with 63%.
My findings are backed up by the weather charts for the month based on the American reanalysis data. This May is already off to a fairly anticyclonic start, I have no idea what if anything this portends for the coming summer without doing more research, at the moment my priority is putting out the washing for my wife.