Crickets and summer nights kinda go hand in hand.
The moment they start chirping, you know: it’s time to forget heavy loads of winter clothing — for a few months at least. Although, with this global warming thing… I guess you are probably confused. 🥴
Every time you hear that chirping, you’re actually eavesdropping to a lovely cricket’s serenade. Okay, that could also be battle cries of various cricket gentlemen, fighting for a female.
As it turns out, chirping, that lovely, almost meditating summer sound can be a pretty accurate thermometer, too.
Hm, how’s cricket’s chirp related to temperature?
Crickets, like other Earth living organisms, have many chemical reactions going on inside their bodies. For instance, reactions that allow cricket’s muscles to contract and produce chirping in the first place.
Crickets are ectothermic (often known as cold-blooded) creatures, like all insects, for that matter.
Such organisms (reptiles, fishes, amphibians, invertebrates) depend mainly on external heat sources, and their body temperature changes with the temperature of their environment.
Why is this important? Well, this pretty much affects how quickly chemical muscle reactions in cold-blooded organisms are happening.
Specifically, a formula called the Arrhenius equation is a simple, but remarkably accurate formula for the temperature dependence of the chemical reaction rate.
As the temperature rises, it becomes easier to reach certain activation energy, thereby allowing chemical reactions, like chirping, to happen more rapidly. Conversely, as the temperature falls, the reaction rates slow, causing the chirping to diminish along with it.
How do crickets make their distinctive chirp?
A process called stridulation — in which certain body parts (there’s a special structure on the tops of their wings, called a scraper) are rubbing together to make a noise — allows crickets to make a chirp.
Generally, only male crickets are singers.
When they want to make their sound, they raise their wings to a 45-degree angle and draw the scraper of one wing across wrinkles on the underside of the other wing, called a file. It’s somewhat like running your finger along with the teeth of a comb.
So, crickets chirp as a way of showing off in front of lady crickets and present themselves as a perfect mating material. As mentioned, their love songs can also help us determine outdoor temperature.
Let’s do a little experiment.
– one summer night- cricket(s), obviously
– stopwatch (use the app on your phone, for instance)
– a paper (or again your phone) to note down the chirps you are about to count
How to Tell the Temperature with Cricket Chirps
We’ll use a formula, like true science-loving people. The formula is derived from Dolbear’s law which states the relationship between the air temperature and the rate at which cricket chirp.
It was formulated by Amos Dolbear and published in an article called “The Cricket as a Thermometer” from 1897. This formula is accurate to within a degree or so when applied to the chirping of a field cricket.
TF = N14 + 40
This equation (which is one of the oldest, the most accurate, and easiest to use cricket-thermometer equations) is published in the Farmers’ Almanac. It should give you the approximate temperature in degrees Fahrenheit.
So, as the formula says, you’ll add 40 to the average number of chirps you count from cricket within 14 seconds.
Example: 30 chirps + 40 = 70° F
To convert cricket chirps to degrees Celsius, count the number of chirps in 25 seconds, divide it by 3 and then add 4 to get the temperature.
Example: 48 chirps / 3 + 4 = 20° C
Or just Google the Fahrenheit to Celsius temperature converter. Or not. Play with it. Use your neuron.
What does your cricket say? What’s the temperature?
Welcome summer! chirp along tonight <3