What insect's chirping rate can be used to estimate temperature? A cricket's chirping rate can provide a rough temperature estimate. This relationship is known as Dolbear's law, named after physicist Amos Dolbear, who published his observations in 1897.
Male crickets produce their familiar song by stridulation: they rub a scraper on one forewing against a file-like ridge on the other. The leathery wings act as resonating surfaces, amplifying the sound. In many species, chirping speeds up as the surrounding temperature rises because the insects' metabolism and muscle activity are temperature-dependent.
The best-known shortcut uses the snowy tree cricket, Oecanthus fultoni. Counting its chirps for 15 seconds and adding 40 gives an approximate Fahrenheit temperature. The method is not universal: each species has its own calling rate, and age, mating condition, and other environmental factors can affect the result.
Crickets are sometimes confused with katydids and grasshoppers, which can also make sounds. However, the classic insect thermometer specifically concerns cricket chirps and Dolbear's law.