The Weather Review

Weather Update

May has just become the sunniest calendar month ever recorded for the UK – immediately breaking the record set in April. Spring 2020 also exceeds the most amount of sunshine for a season, with only three summers being sunnier: 1976, 1989 and 1995.

It was also the eighth warmest spring on record and the fifth driest. The main reason for the exceptional weather is the persistent high pressure over the country. While some summers are hotter, owing to warmer air masses moving over the UK, the intense sunlight this month comes from the lack of cloud formation or rain. High-pressure areas are points in the lower atmosphere where air is losing heat and falling. The air pushing down stops evaporated water particles from the surface from rising to condense into clouds. A clear sky as we head into European summertime means long days of direct solar radiation.

The dry conditions may lead to lower than normal river levels in Europe. This stops cargoes being delivered on rivers such as the Rhine in Germany, while the warmer waters mean nuclear plants cannot operate at full capacity, as they need lots of cold water for cooling. This could lead to price spikes when there are not enough power plants to provide electricity. We saw this during the heatwave in June 2019, when French nuclear plants had to shut down.

Conversely, during this month a combination of lockdown and sunny, windy weather caused problems for the national grid, who had to pay millions of pounds to generators to stop an excess of energy flooding our electricity system. During recent weeks power prices were negative and as low as -£72/MWh with too much solar power being generated meeting low electricity demand.

Looking forward, some analysts expect June could be the most anomalously warm month this year, although in the next week or so expect more blustery and rainy conditions. The jet stream is continuing to meander (linked to loss of arctic sea ice), bringing more extreme weather and cold periods. Hopefully later in the month some warmer tropical air will drift over, to enjoy socially distant from one another.