Record-breaking rainfall

Those interested in the UK’s climate records have only had to wait two months of the new decade for a significant new rainfall record to be set.

February 2020 set a new UK record for February rainfall in a series stretching back to 1862. Storms Caira, Dennis and Jorge, brought 44% of the month’s rainfall, beating the previous record that was set in 1990.

Rainfall amount Winter 2020 UK

Three individual peaks stand out in the February 2020 daily rainfall record. These peaks from left to right are: Storm Ciara; Storm Dennis; and Storm Jorge.

Dr Mark McCarthy is head of the Met Office’s National Climate Information Centre. He said: “Of the top ten wettest winters, four have occurred since 2007 and seven since 1990. Associated with these changes we have also observed a 17% increase in the total rainfall from extremely wet days and a paper published in 2014 showed the 2010s contain more monthly to seasonal UK rainfall records than any other decade in the observational record.”

Dr Mark McCarthy – a guest on the Met Office’s Weather Studio Live – discusses rainfall variability in a changing climate. More content from Weather Studio Live is available here

This record-breaking February is consistent with a previous Met Office study in Nature Communications – published in 2017 – showing a high chance of one or more UK regions experiencing record monthly rainfall each winter in the current climate.  To understand the likelihood of new rainfall records, you need to understand that the rainfall record in the UK is subject to a very wide range of natural variation both within years and between years, as well as the effects of the climate change we have accrued so far.

February 2020 UK rainfall map

There was more rainfall recorded across the UK in February 2020 than has been recorded in any previous February in a series stretching back to 1862.

This latest rainfall record agrees with the Met Office’s estimates for the government’s National Flood Resilience review 2016 which took into account current climate change and the range of natural variability of climate.

Professor Adam Scaife is the Met Office’s head of long range forecasting. He said: “In that report and the subsequent science paper, we showed that there is a one-in-three chance of one or more UK regions experiencing record monthly rainfall each winter.”

The method – known as UNSEEN* – used thousands of simulations of UK winters run on the Met Office supercomputer to estimate the chances of record rainfall events.

Prof. Scaife said: “In recent times, we have seen events for which there was no observational precedent but using the UNSEEN method, large numbers of computer simulations of UK winters can tell us about the really extreme cases, like February 2020, that break the current record.

“The record February rainfall is in agreement with these estimates based on the latest science and we should expect similar events in coming years.”

* UNprecedented Simulated Extremes using ENsembles

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