Imagine you’re camping deep in the woods on a summer night. The sun sinks below the horizon and the temperature begins to fall. You shiver, and as you pull your jacket around your shoulders, you wonder just how cold it really is. Here’s a clever way for you to find out,and all you need is 1. Wrist watch 2. Your ears 3. A little of patienceStart by listening for a chirping cricket. Male crickets around the world make this characteristic sound by rubbing their wings together. The edge of a male cricket’s right wing is covered with little ridges, like a file or a washboard. As he rubs his left wing cover across the uneven right wing, he produces an insect love song that female crickets find irresistible.

    Female crickets use this amorous chirping to find their perfect mate, listening with a pair of special ears located below the knees. Now you can use these same serenades to calculate the temperature.

    Most insects tend to be more active when it’s hot, and more sluggish in cooler weather. Crickets are no exception to this rule.

    In cold weather, a cricket will do everything more slowly, and as the temperature drops, so does the tempo of his love song. By measuring how quickly he chirps, you can find out approximately how cold it is.

    It’s easy to do: Simply count the number of chirps a single cricket makes in a fifteen second period, then add thirty seven. Although individual species might be a little faster or slower, this should give a fair approximation of the temperature in degrees Fahrenheit.

    Remember: fifteen seconds worth of chirps, plus thirty seven. Even if the chirping keeps you awake all night, at least you’ll know the temperature.