Hydrological Summary for May 2020 Published

May was exceptionally dry and sunny (the sunniest for any month since records began in 1929), reducing soil moisture to record-breaking lows, and continuing widespread river flow recessions. Total rainfall was around half the average for the UK as a whole and less than a quarter across much of England and Wales. It was the driest May on record for England & Wales, which concluded the third driest spring (March-May), both in series from 1910. Wildfires were reported in several locations around the UK. River flows were mostly below average and new May monthly minima were established on some rivers, especially in Wales. The continued dry conditions further increased soil moisture deficits (SMDs) to their driest for the end of May for the UK (in a series from 1961). Groundwater levels fell across the UK but at month-end were generally in the normal range or above due to the wet winter. Reservoir stocks fell, and were at their lowest recorded for the end of May for England & Wales as a whole (in a series from 1990). With river flows low and reservoir stocks depleted entering the summer, there is potential for continued agricultural stress, and an increased pressure on water resources in some northern and western areas. Current seasonal outlooks suggest persistence of below normal flows across much of the UK (although early June has been more unsettled with some heavy rainfall).

Read the Hydrological Summary