Crickets Chirping Thermometer

Dolbear's law is a formula discovered by physicist Amos Dolbear in 1897 that relates the temperature to the rate of cricket chirps. The law states that you can estimate temperature by counting cricket chirps because crickets are cold-blooded and chirp faster in warmer temperatures. See also our Reptile Enclosure Size Calculator.

Male crickets chirp primarily to attract females for mating. They also chirp to establish territory and communicate with other crickets. The chirping is produced by rubbing their wings together in a process called stridulation.

Crickets produce their characteristic chirping sound through stridulation - they rub their wings together. One wing has a serrated edge that acts like a file, while the other wing has a scraper. When rubbed together, this creates the chirping sound we hear.

The cricket thermometer can be surprisingly accurate, typically within 1-2 degrees Fahrenheit of the actual temperature. However, accuracy depends on factors like cricket species, humidity, and background noise levels.

The common field cricket (Gryllus assimilis) works best for Dolbear's formula. Tree crickets can also be used but may require different formulas. Snowy tree crickets are considered the most accurate natural thermometers.

This method works best on calm, clear evenings when crickets are most active. It's less accurate during windy conditions, rain, or when temperatures are below 55°F (13°C) as crickets become less active in cooler weather.

The traditional method involves counting chirps for 14 seconds, then adding 40 to get the temperature in Fahrenheit. You can also count for 15 seconds and add 37, or count for a full minute and use different formulas for more accuracy.