Cricket Chirp Thermometer Calculator — Dolbear's Law
Use cricket chirps as a natural thermometer: count the chirps per minute and this calculator applies Dolbear's Law (or species-specific variants) to estimate the ambient temperature in °F, °C, and K.
Cricket species / formula
Estimated ambient temperature from chirp rate
- 1
Subtract chirp offset
N − 40 = 80 − 40 = 40 - 2
Divide by species divisor
40 ÷ 4 = 10 - 3
Temperature °F (add base)
50 + 10 = 60Dolbear's Law: T_F = base + (N − offset) / divisor
How does this calculator work?
Dolbear's Law: T_F = 50 + (N − 40) / 4, where N = chirps per minute (snowy tree cricket). Quick shortcut: count chirps in 14 seconds and add 40 for °F. Convert to °C with (T_F − 32) × 5/9. Accurate to roughly ±3–5 °F under calm conditions.
Formula
How this is calculated
In 1897, American physicist Amos Dolbear published "The Cricket as a Thermometer," observing that the chirp rate of the snowy tree cricket (Oecanthus fultoni) is closely correlated with ambient temperature. His formula — T_F = 50 + (N − 40) / 4, where N is chirps per minute — works because crickets are ectotherms: their muscle contraction speed, and therefore their chirping rate, is driven directly by surrounding temperature.
Dolbear's Law is species-specific. The snowy tree cricket gives the tightest relationship and is the basis for the classic "count chirps for 14 seconds and add 40" rule of thumb (which approximates the same formula). Field crickets and katydids have slightly different coefficients because their neuromuscular systems respond to temperature at different rates. This calculator lets you select the relevant species to apply the correct variant.
The method is accurate within roughly ±3–5 °F under calm, consistent conditions, but humidity, wind, the cricket's age, and individual variation can all shift the result. Treat it as a fun approximation, not a precision measurement — and always listen to multiple crickets to get a representative count.
Frequently asked questions
Count the number of chirps in 14 seconds and add 40 — the result is the temperature in °F. This approximation comes directly from Dolbear's formula for the snowy tree cricket and is accurate to within a few degrees in typical outdoor conditions.
Crickets are cold-blooded (ectotherms), so the speed of all their chemical and muscular processes is dictated by ambient temperature. Warmer conditions speed up their enzyme kinetics, making their wing-rubbing muscles contract faster — and producing more chirps per minute.
No — different species have different coefficients. The snowy tree cricket gives the tightest fit; field crickets and katydids are less reliable. The formula also breaks down below about 55 °F (13 °C), because crickets become inactive in the cold.
TG we-Calculate Editorial Team. (2026). Cricket Chirp Thermometer Calculator — Dolbear's Law [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/cricket-chirp-thermometer-calculator
TG we-Calculate Editorial Team. "Cricket Chirp Thermometer Calculator — Dolbear's Law." TG we-Calculate. 2026. https://we-calculate.com/calculator/cricket-chirp-thermometer-calculator.
TG we-Calculate Editorial Team, "Cricket Chirp Thermometer Calculator — Dolbear's Law," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/cricket-chirp-thermometer-calculator
@misc{wecalculate_cricket_chirp_thermometer_calculator, title = {Cricket Chirp Thermometer Calculator — Dolbear's Law}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/cricket-chirp-thermometer-calculator}}, year = {2026}, note = {TG we-Calculate} }
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