September brought a temporary interruption to the dry conditions that had characterised much of summer 2026, with unsettled weather delivering near-average rainfall for the UK as a whole. However, rainfall distribution was uneven, with Scotland and Northern Ireland wetter than average while much of England remained substantially drier than average. Soil moisture increased across many western and north-western COSMOS-UK sites compared with the previous month, while much of England experienced further drying and remained drier than usual for the time of year. Despite responses to mid-month rainfall, most rivers in England and Wales continued to record below normal to exceptionally low flows. Seasonal groundwater recessions continued across much of the UK, with only limited signs of early autumn recharge, while reservoir stocks for England & Wales declined further. Wimbleball and East Lothian recorded their lowest September reservoir stocks (in records since 1988), the second consecutive month for Wimbleball and the third for East Lothian. All of England and the majority of Wales remained in drought status or prolonged dry weather. By month-end, the Scottish Tyne and Tweed catchments were in moderate scarcity, while southwest Wales had moved to recovery from drought status. Recovery, starting from a below-average baseline, will require above-average rainfall during autumn and winter. Although seasonal forecasts favour wetterthan-average conditions over the next three months, the Hydrological Outlook indicates river flows and groundwater levels in parts of south-east England are likely to remain below normal. Autumn and winter recharge will be important in determining water resources pressures in 2027.