Level of annual rainfall

IBISWorld estimates that average rainfall will increase by 63.9 millimetres over the five years through 2022-23 to average 1,120 millimetres. Rainfall can have wide-ranging impacts on the UK economy, in particular agriculture for field grown crops. Rainfall in large quantities may also disrupt construction output, transport and retail businesses. Rainfall in the United Kingdom is largely determined by the jet stream, which moves weather systems around the globe. The weather is influenced by differences in temperature between the cold air in the north and warm air in the south and rain results when warm moist air cools and condenses to liquid. Large differences in temperature between the hot and cold air can lead to storms, bringing rain in significant quantities.

The summer of 2018 was dominated by warm weather which significantly reduced the amount of rainfall, especially for regions in the South East. According to the Met Office, it was the warmest on record for the three-month period between June and August. Over 2019-20, a 35.3% rise in rainfall, reaching the highest level of rainfall for over 20 years and contributing to poor crop yields during the year. In October 2020, heavy rain across the United Kingdom led to flood warnings for parts of East Scotland, West Midlands, England and Wales. Following a dry first half of 2021-22, rainfall declined 10.7% over the year.