heat wave

Noun

heat wave (plural heat waves)

1. (idiomatic) A period of exceptionally hot weather.
   • We're havin a heat wave / A tropical heat wave / The temperatures rising, it isn't surprising / She certainly can, can can! / She started a heat wave / By letting her seat wave, / in such a way that the customers say / that she certainly can, can-can!1933, Irving Berlin, “Heat Wave”, in As Thousands Cheer

   Antonyms:

   cold spell, cold wave

   1. (US, idiomatic) Three consecutive days with daytime high temperature of 90 degrees Fahrenheit or higher.
   2. (UK, idiomatic) A period of at least three consecutive days with daily high temperatures of the respective county's temperature threshold or higher.
2. An electromagnetic wave in the infrared spectrum.