Global analysis finds heatwave seasons lengthened by nearly nine days per decade

Sep 23, 2:40 PM UTC

Earlier starts and later endings extend the average season

A study published September 23 found that the global land heatwave season lengthened by an average 8.71 days per decade from 1979 through 2023. Heatwaves began 3.29 days earlier and ended 5.41 days later per decade on average. Longer-season trends appeared across 92.1% of land, but were statistically significant across 34.4%, an important distinction between trend direction and confidence. The observational analysis also identified faster onset of recent first heatwaves and larger timing shifts in drylands.

Nature Climate Change — Earlier and faster heatwave onset on land under a warming climate