WICHITA, Kan. (KSNW) — Crickets can be nature’s thermometers – sort of. There is a unique relationship that occurs between cricket chirps and the air temperature outdoors. But, before we understand that relationship, we first need to learn more about crickets. These cold-blooded insects are actually closely related to both the grasshopper and katydid families.
Their lifespan may be longer than you would imagine, as many can live beyond a year but tend to struggle to survive past one winter. However, toward the middle and end of the summer season, they are everywhere outdoors, and you can hear their familiar song most nights.
What is unique about these insects is that in both males and females, their ears are located on their legs. However, it is only the males that you will hear chirping. They communicate by rubbing their front wings together to make that distinct sound.
How high or how low the pitch of the chirp sounds has a lot to do with the air temperature outside. The temperature will impact the frequency of the chirp. When temperatures are cooler, the pitch of the chirp is lower, and the frequency is much less than when the temperatures are warmer. A warmer temperature will also lead to a higher chirp. Temperatures below 55° or above 100° are too extreme for their cold-blooded bodies to make much noise.
The males chirp to find a female or compete for a female, or they are communicating the threat of danger nearby. The most common crickets we see here in Kansas are the snowy tree cricket and the field cricket. A snowy tree cricket is a vibrant green color and will make a more continuous sequence of chirps during a set amount of time. The more common cricket is the field cricket which is brown to almost black in color, but the frequency of chirps can vary more in this species.
Amos E. Dolbear, who was a physics professor at Tufts College, decided to study the relationship between cricket chirps and temperature. In 1897, Dolbear’s Law was created and stated that there was indeed a correlation between the snowy tree cricket chirps, specifically during the span of a minute, and that it was related to the air temperature in degrees Fahrenheit. Calculations have been found to be fairly accurate when compared to thermometer readings.
Due to less consistency in the chirps of a field cricket, a different equation had to be made when studying the temperature and cricket chirp relationship. If you are unsure which cricket is singing, the generalized equation of T=C+40 can be used. ‘T’ stands for the air temperature, and ‘C’ represents the number of chirps heard in a span of 15 seconds.
Test it out the next time you are outdoors and have your Storm Track 3 App handy to see how close the approximation of the cricket method is to the actual air temperature. Also, see if you notice a difference in the frequency and pitch of chirps on cooler evenings versus warmer evenings. It might be a fun experiment to do with friends and family!
— Meteorologist Erika Paige