Dolbear's law

Dolbear's law states the relationship between the air temperature and the rate at which crickets chirp.

[1][2] It was formulated by physicist Amos Dolbear and published in 1897 in an article called "The Cricket as a Thermometer".

[1][2] However, the snowy tree cricket was misidentified as O. niveus in early reports and the correct scientific name for this species is Oecanthus fultoni.

Dolbear expressed the relationship as the following formula which provides a way to estimate the temperature TF in degrees Fahrenheit from the number of chirps per minute N60:

A shortcut method for degrees Celsius is to count the number of chirps in 8 seconds (N8) and add 5 (this is fairly accurate between 5 and 30 °C):

This formula was referenced in an episode (Season 3, Episode 2, "The Jiminy Conjecture") of the American TV sitcom The Big Bang Theory (although Sheldon referred to Amos Dolbear as Emile Dolbear and gave the year of publication as 1890).

Richard Powers, author of the Pulitzer Prize-winning [The Overstory] (2018, W.W. Norton & Co.), has his fictional character Patricia Westerman use the formula (chapter 11.