Climate and Flooding

Weather and Climate

The Met Office publishes monthly statistics collated at RNAS Yeovilton weather station. Data for temperature and rainfall go back to 1965, and sunshine figures start in 1983.

Highlights for the 1965-2021 period are as follows:-

• Average temperatures are on an upward trend, with 2020 having the highest recorded average maximum temperature (see Chart 5 below)
• Despite this upward trend, the coolest year in the period was 2010, with the lowest average minimum temperature, and 90 days of air frost.
• The average annual rainfall is 725mm.
• The driest year in this 56-year period was 2003, with just 473mm of rain (see Chart 6 below)
• 2012 was the wettest year, with 987mm of rain – more than double that of 2003.
• The sunniest months were April 2018 with 99.1 hours of sunshine, and March 2017 in close second with 98.6 hours.

Source: Met Office

Flood Risk

Around 18% of Somerset is either at or just above sea-level. The Somerset Levels and Moors are one of the lowest areas in the UK, they cover over 60,000 hectares which are particularly at risk of severe flooding as a result of extreme weather periods.

There are 21 permanent pumping stations in Somerset that are managed by The Environment Agency, these are set to automatically operate according to water levels, and are often in operation during the winter months when rainfall is higher. In addition to this the Environment Agency can deploy mobile pumps when flooding is likely. This is assessed based on 3 ‘triggers’ including amount of rain forecast, and the speed of water levels rising.

In early 2014, the Levels experienced widespread flooding within the Parrett and Tone river catchments. With an estimated 100 million cubic metres of floodwater covering an area of 65 square kilometres, it is the largest flood event ever known.

As a result, the Somerset Levels and Moors Flood Action Plan (FAP) was produced by a range of organisations, with the involvement of the community and co-ordinated by Somerset County Council. As part of the 20-year plan, the Somerset Rivers Authority was established in 2015, with the purpose of providing extra levels of flood protection and resilience.

Part of the Flood Action Plan is the Bridgewater Tidal Barrier – a large structure across the river Parrett with gates that can be closed when the tide is expected to be particularly high. This will prevent high water levels from travelling upstream and causing flooding, and will better protect over 11,000 homes and 1,500 businesses. Downstream defences will also be maintained or raised to work alongside the barrier.