Well, first of all, don’t stick a cricket under your tongue to tell the temperature.
That won’t give you the information you seek, and nearly always damages the insect.
First, some background: Cricket metabolism slows at a consistent rate when they get cold and speeds up when they get hot. This is true of not just crickets but all cold-blooded creatures. However, crickets make especially good thermometers because they chirp regularly and incessantly.
The intervals between chirps become an indicator of temperature on cold nights, they slow down; on hot nights, they speed up. If you count the number of cricket chirps and do some simple math, you can get a moderately accurate sense of the temperature.
Here’s the simplified formula first, the one taught in nature class: To get a close approximation of Fahrenheit temperature, count the number of chirps in fifteen seconds and add 40. If you prefer your crickets on a metric scale, count the number of chirps in a minute, add 50 and divide by 9.
But what if an estimate isn’t good enough for you, and you want a more precise measurement? Well, then, you have to calibrate your instrument. First of all, determine what kind of cricket you’re using. All of the results below give you the temperature in Fahrenheit:
If your cricket is black, it’s a common field cricket. Count its chirps for fifteen seconds and add 38. If your cricket is small and pale green, and you found it on a tree, it’s a tree cricket. Count the number of chirps for seven seconds and add 46.
If it’s white, and it’s in a tree, you’re in luck, you’ve got a snowy tree cricket, the most accurate cricket of all. Count its chirps for fourteen seconds and add 42.
Just one final warning, the cricket thermometer is only accurate in summer weather, not in the chill of other seasons.
For example, if there’s snow on the ground and you hear zero chirps out there, you can’t do the math and conclude that the temperature is 40 degrees.