From Glossary of Meteorology


An oppressively uncomfortable state of the weather that results from the simultaneous occurrence of high temperature and high humidity. It is often enhanced by calm air and cloudiness.

This term is gaining technical recognition in light of the increased study of human comfort and air conditioning. Sultriness has been expressed in terms of the values of various measures of comfort. Some of the lower limits are water vapor pressure of 14 mm; dewpoint of 19°C (65°F); equivalent temperature of 56°C (133°F); effective temperature of 24°C (75°F); and the following pairs of temperature and relative humidity, 35°C (95°F) and 25%, 30°C (86°F) and 40%, 25°C (77°F) and 65%.
See comfort chart, comfort zone.