River flow

July was an unsettled month and one of notable contrasts. Though temperatures cooled decisively thereafter, record‑breaking heatwave conditions characterised the 1st of the month. Following overnight temperature minima which exceeded 20°C in the south-east, Heathrow recorded 36.7°C, the warmest July day on record for the UK (in a series from 1853) and the hottest day in the UK since 2003. Throughout July, the north of the UK was generally wet and cool, whilst in southern areas conditions were predominantly dry although interspersed with intense downpours and thunderstorm activity.

The outlook for August is for normal to below normal flows across England and Wales, with an increased likelihood of below normal flows in some groundwater-fed catchments of southern and eastern England. For England and Wales, the outlook for the next three months is similar to that for August The outlook for Scotland is uncertain in the coming months but normal to above normal flows are most likely in the south and east and normal to below normal flows in the north. Groundwater levels are likely to be normal to below normal in August throughout the UK.

The outlook for July is for below normal flows across much of England and Wales, with the possibility of notably low flows in some areas. In north-western areas of the UK including north-west England, July is likely to see normal flows. This pattern is likely to persist over the next three months, although it is likely that river flows will return to normal across Wales. For groundwater, levels in July are most likely to be normal or below normal, and this is likely to continue over the next three months.

Overall, June was dry, especially in parts of south-east England, and sunnier than average. Monthly average temperatures were fairly typical for June but it was slightly warmer than average in the far south-east and there were some warm spells, with heatwave conditions developing through the final days and extending into early July. As expected for the time of year, soil moisture deficits (SMDs) climbed steeply and, correspondingly, the seasonal recession of river flows and groundwater levels continued, leading to some notably low late June river flows.

The outlook for May suggests normal river flows are likely in northern Britain, and normal to below-normal flows further south. This reflects the notably low April rainfall across England and Wales, with less than half the monthly average received in most areas; however, early May has been very wet in all regions, which decreases the likelihood of very low flows and increases the chances of above-normal flows in the north. The groundwater outlook is for a similar picture to April, with mostly normal and below-normal levels.