With less than a week of February to go, conversations are already being had about how dry the month has been, and what impact this could have.
This month, we’ve been exploring the theme of water security and climate change. But in more granular detail, February 2023’s lack of consistent rain for most of the UK underlines some of the common differences between weather and climate, and where there’s an overlap in challenges.
The summer of 2022 saw record-breaking temperatures when 40.3°C was recorded for the first time in the UK. The first eight months of that year were also the driest since the infamously dry start to 1976. With these notable weather events in mind, water resources have often been in the news, and a drought was declared by the Environment Agency for many parts of the UK in August 2022.
That declaration of drought was subsequently removed for most areas as Autumn rainfall topped up resources for many, though not all.
Drought comes down to a range of factors and is much more complex than just rainfall amounts, with hydrology, geography and infrastructure also influencing drought conditions and the availability of water in the UK’s reservoirs. However, a dry February has led to some speculation about weather trends in recent weeks.
Month so far
Up to 20 February, you’d expect to have around 71% of the month’s total average rainfall. However, the UK has currently had just 36% (34.5mm) so far, according to provisional Met Office figures.
High pressure has been largely responsible for a dry first half of February.
But when you look into the regional data, the lack of rainfall becomes more marked. While Scotland has so far had 59% (83.5mm) of its average February rainfall, the south of England has had just 6% (3.8mm). For England it has been the driest 1st to 20th February since 1993.
Some individual counties also stand out due to a lack of rainfall. Hertfordshire has had an average of just 0.7mm of rain so far this month – just 1% of its average for the whole month. At the time of writing 14 counties in central and southern England had recorded less than 2mm of rainfall so far this month.
Of course, these figures will change by the end of the month, but it does give an indication of quite how dry this February has been so far. For many of these areas the dry spell began in mid January. Pershore in Worcestershire for example has had just 1.6mm of rain since 15th January and for many counties of central and southern England the period from mid January to now has been a notable, but not record breaking, winter dry spell.
Mark McCarthy is the manager of the National Climate Information Centre at the Met Office. He said: “Although there’s still around a week left of February, it has been a notably dry month so far, especially in the south of England.
“In short, high pressure has been dominant over the UK, helping to repel rain-bearing systems across much of the country, though many have managed to influence north-western areas at times.”
Sam Larsen, Director of Programmes and Planning at Water UK, said: “Water levels in the environment began to pick up following last summer’s drought conditions, but low rainfall this month means a majority of UK rivers are below normal levels for this time of year, meaning there is less water available for nature, agricultural abstraction, and public water supply.
“It remains to be seen whether rainfall levels will pick up before summer. This, along with the lasting impacts of climate change and population growth, means it’s absolutely vital that we all continue to save water and help safeguard against potential future drought conditions. For hints and tips on how to save water, money and energy, visit www.watersworthsaving.org.uk.”
It has been notably dry in the south of England.
A changing climate and natural variability
Climate change projections show an increasing likelihood of hotter, drier summers and warmer, wetter winters, though the natural variation of rainfall patterns in the UK means this won’t be the case every year. The month of February is itself a good indicator of the variability of the UK climate with the driest month for the UK in a series back to 1884 being February 1932, when just 9.5mm of rain fell. In contrast, February 2020 was the fourth wettest month on record with 213.7mm of rain.
Mark continued: “A wet Autumn last year helped to recover some of the rainfall deficits built up through the earlier part of 2022, but the winter has seen two long dry periods firstly in early December and then from mid-January and through February, interspersed with a more notably wet and unsettled period in late December and early January. This reflects the variability of a UK winter which is an important consideration when considering the challenges presented by both short-term weather events and longer-term changes in our climate.”
The figures sited in this blog are provisional Met Office figures up to 20 February 2023.