A heat wave is a prolonged period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary, a heat wave is measured relative to the usual weather in the area and relative to normal temperatures for the season. Temperatures that people from a hotter climate consider normal can be termed a heat wave in a cooler area if they are outside the normal climate pattern for that area.

Heatwave! is an American disaster movie that was broadcast on the ABC television network on January 26, 1974. It was an ABC Movie of the Week. Its running time was 90 minutes. The film was directed by Jerry Jameson, produced by Herbert F. Solow and Harve Bennett.