State of the UK Climate 2023

The 2023 State of the UK Climate report - published 24th July 2024

2023 was the second warmest year on record for the UK in the series from 1884, with only 2022 warmer. 2023 was 0.83°C above the 1991–2020 average and 1.66°C above 1961–1990. February, May, June and September 2023 were all ranked in the top-ten warmest months for the UK in the monthly series from 1884. The UK's second warmest year of 2023, the warmest June and the September heatwave were all made more likely by climate change.

Nature’s Calendar data contributed to the phenology section of the report:

• Indicators for spring 2023 were generally near-average or later compared with the 1999–2022 baselines. Insect activity, in particular, appeared later. However, Hazel had its earliest flowering date in a series from 1999.
  
  
• Bare tree dates were a few days later than the 1999–2022 baseline due to warm September temperatures and a generally mild autumn.
  
  
• Overall, the 2023 leaf-on season was slightly longer than the 1999–2022 baselines, although the shorter lawn-cutting season might be attributed to a complex mixture of low temperatures in early March inhibiting growth and wet grass in autumn discouraging late cutting.

In terms of significant weather events, 2023 saw the UK record its warmest June on record by a wide margin in a series from 1884, with a major North Atlantic marine heatwave a significant contributing factor. 30°C was recorded in September in the UK on seven consecutive days, for the first time on record.

The year also included Storm Babet, which brought the UK's most impactful weather event of the year. England and Wales combined had its third wettest 3-day period on record on 18–20 October in a daily series from 1891. Furthermore, Scotland had its wettest 2-day period on record on 6–7 October in a daily series from 1891. 

Winds from storm Ciarán on 2 November had the potential to be as severe as from the ‘Great Storm’ of 16 October 1987, but the strongest winds missed the UK to the south. Finally, the UK recorded its wettest September to December period since 2000 due to persistently wet and unsettled weather, including the sequence of named storms from Agnes to Gerrit.