heatwave

plural heatwaves

1. alternativeAlternative spelling of heat wave (“period of exceptionally hot weather”)

   Both weather agencies forecast temperatures above 40C over the coming days and called for vigilance amid forecasts of “a very intense, even exceptional” heatwave in parts of the continent.

   2025 August 11, Ajit Niranjan, “Southern Europe swelters under deadly heatwave as temperatures pass 40C”, in The Guardian, →ISSN

   1 more example

   Various parts of the world have been experiencing heatwaves and on Thursday the EU’s climate monitoring service said the world had experienced its hottest June on record last month. […] In parts of China, an enduring heatwave has continued, with temperatures reaching above 35C.

   2023 July 7, “UN says climate change ‘out of control’ after likely hottest week on record”, in The Guardian, →ISSN

   Antonyms: cold spell, cold wave

2. A heat haze.

   On a hot summer's day, one can literally see heatwaves shimmering off the surfaces of inanimate objects.

   2021, Murray du Plessis, Modern Meditations: 101 Ways to Slow Down & Connect to Spirit