Overall, May was a warm month with above average temperatures recorded across the country. Although the UK rainfall was near-average, there were regional differences. Parts of south-east England and south Wales saw localised thundery showers throughout May and received above-average rainfall. In contrast, rainfall was below average in northern England, south-west England and eastern Scotland, notably so in some areas. In response to the generally dry conditions in May, soil moisture deficits climbed and were near-average at month end, a contrast from the minimal deficits at the end of April. Reflecting the rainfall patterns in May, river flows were generally in the normal range, with below normal flows in south-western and northern England. Correspondingly, reservoir levels are moderately below average at some impoundments in northern and south-western England, following steep declines through May. However, overall reservoir stocks are near-average at the national scale. This, coupled with normal to above normal groundwater levels across the main aquifers, implies that the water resource outlook for the summer remains favourable.
The full Hydrological Summary can be found here.