Water situation report

May was the third consecutive month when below average rainfall was recorded across south-east England, with just 50% of the long-term average (LTA) rainfall fell. The south-east recorded the driest two months for April and May since 2011. The lack of rainfall and record-breaking high temperatures during the last week of May caused soil moisture deficits (SMDs) to rise steadily during the month. The SMDs ended more than a third higher than the end of month LTA, and similar to the SMDs in May 2025. The combination of low rainfall and very high SMDs resulted in little or no aquifer recharge across the south-east. River flows fell throughout the month and only a handful of places showed any notable response to the heavy rainfall on 18 May. Groundwater levels fell at all key indicator sites across the southeast and ended the month as normal for May at most sites. June was a wet month with an average of 136% of the long-term average (LTA) rainfall recorded across the south-east of England as unsettled conditions emerged after the high pressure experienced in May. Thames area (THM) was the driest area and Kent, South London and East Sussex area (KSLES) was the wettest. The first 11 days of the month accounted for an average of 82% of the monthly total rainfall. A heatwave developed from 20 June with unprecedented temperatures, resulting in red heat alerts being issued by the Meteorological Office for three days from 24 June. There were extensive overnight convective thunderstorms on 22 June in an arc from central THM, to southern Hertfordshire and North London area (HNL) to northern KSLES. These storms resulted in daily rainfall totals of over 30mm in these areas. As would be expected, the soil moisture deficits (SMDs) rose to end the month of June above the LTA and there was little recharge. Groundwater levels have continued to fall across the southeast of England.

Jane Allam, Environment Agency