Crickets can’t predict the weather, but their chirp can tell you the temperature.

Crickets are ectotherms — meaning their body temperature depends on the temperature of their surrounding environment.

Much like a sluggish bumble bee on a cool spring morning or a lizard sunning on a rock, crickets move slower in cooler temperatures.

As crickets warm, they can rub their wings together faster, which is how male crickets make the nightly repetitive chirp they use to attract mates.

The relationship between cricket chirping and temperature has been noted for a long time. In Western science, it is called Dolbear’s law after the most widely referenced early publication on the phenomenon published in 1897 by Amos Dolbear.

Dolbear’s observations showed that you can count the number of chirps per 15 seconds, add 40, and that will give you the temperature in Fahrenheit.

The National Weather Service Weather Forecast Office in El Paso, Texas has set up an online calculator based on Dolbear’s law.

To use the calculator, users simply enter the number of chirps and it will provide the temperature.