Daily temperature extremes have risen by up to 4C over the last 50 years, say climate experts from the Met Office Hadley Centre.
Research published this month in the Journal of Geophysical Research explored how observed extreme daily minimum and maximum temperatures, across different world regions, have changed since 1950.
Minimum temperatures have seen the biggest increases, most notably over Russia and Canada, where the coldest days are now up to 4 C warmer than they were in the middle of the 20th Century.
The largest changes in maximum temperature were found across Canada and Eurasia where they have typically warmed by 1 to 3 C. Warming across the UK was found to be between 0.5 and 2 C.
Simon Brown, Met Office Climate Scientist said: "This latest research shows that some extreme events are already increasing. The trend is set to continue with our changing climate having a significant impact, with warmer nights and hotter days in the future."
The Met Office is working with many different sectors to explore the impacts of climate change. Warmer nights and hotter days will have wide ranging impacts from heat waves, such as the one that affected Europe in 2003, to changes in crop growing seasons.
