Rainfall Frequency in England: Weather Patterns and Extreme Events

Rainfall Frequency in England: Weather Patterns and Extreme Events

Rainfall in England is influenced by several factors, including the movement of weather patterns across the world and the temperature of the air, which can hold more moisture as it warms. The climate of England is characterized by a temperate maritime climate, with annual rainfall averaging around 1,154mm (45.43 in). This article explores the rainfall patterns in England, focusing on the subtopics of the weather in England and the frequency of extreme rainfall events.

Weather Patterns in England

England's climate is influenced by the Atlantic Ocean, with most rainfall occurring in autumn and winter, when Atlantic depressions are most active. In summer, rainfall is caused by sun heating the ground, leading to convection and showers and thunderstorms. The average number of rainy days in England is around 156.2, with an average yearly rainfall of 1,154mm. Coastal areas of the south-west, such as Cornwall and Devon, typically receive 900–1,000 mm (35–39 in) of rainfall annually, while higher ground areas, like Dartmoor, Exmoor, and Bodmin Moor, may receive up to 2,000 mm (79 in).

The Azores High, a high-pressure system, also influences the south-west of England, reducing cloud cover and causing less convective cloud cover in spring and summer. In coastal areas, there are more hours of sunshine compared to inland areas, where higher ground causes less convective cloud cover and reduces the amount of sunshine.

Extreme Rainfall Events in England

Recent studies have shown that extreme rainfall events could become more frequent in the UK, with some areas experiencing up to four times as many events by 2080 compared to the 1980s. Under a high emissions scenario (RCP 8.5), rainfall events in the UK could exceed 20mm/hr, which is important for aspects of planning such as surface water drainage and flood risk. The greatest change in the intensity of extreme hourly precipitation for every degree of warming is indicated by the blues in the Northwest of the UK, with the red and orange colours showing less change.

Planning and Preparation

Local governments can use climate projections to better prepare for changes to rainfall in the future. The latest set of UK climate projections (UKCP18) indicate that on average, winters will continue to become wetter and summers drier, with an increase in the number of extreme rainfall days. By understanding how our changing climate affects these systems regionally, local governments can implement measures to mitigate the impacts of extreme rainfall events, such as improving surface water drainage and flood risk management.