If I don't have a thermometer handy, can I count cricket chirps to calculate the temperature outside?

Yes! The current temperature can be estimated by using a simple mathematical calculation involving counting the number of times a cricket chirps over a period of time. Male crickets chirp (usually at night when it’s cooler) to attract female crickets and to scare other males away from their territory. The chirping sound is made by the male cricket rubbing together little teeth on its wings. The frequency of chirping varies according to temperature. When the temperature rises, so does the frequency of the cricket’s chirp. To get a rough estimate of the temperature in degrees Fahrenheit, count the number of chirps in 15 seconds and then add 37. The number you get will be an approximation of the outside temperature.