What this calculator does
Cricket chirp thermometer works out estimate air temperature from a cricket’s chirp rate using Dolbear’s law. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaT(°F) = base + (chirps/min − offset) / divisor (Dolbear, 1897); field cricket: 50 + (N−40)/4
The inputs explained
| Field | What to enter |
|---|---|
| Species | Choose from Field cricket, Snowy tree cricket, Common true katydid. |
| Chirps counted per minute | A number. Starts at 80. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with chirps counted per minute
Every other input is held at the calculator’s starting values while chirps counted per minute varies. Select any row to load that scenario into the calculator.
How the answer changes with chirps counted per minute
| Chirps counted per minute | Estimated temperature | Estimated temperature | Species formula used |
|---|---|---|---|
| 40 | 50.0 °F | 10.0 °C | Field cricket: 50+(N−40)/4 |
| 60 | 55.0 °F | 12.8 °C | Field cricket: 50+(N−40)/4 |
| 80 | 60.0 °F | 15.6 °C | Field cricket: 50+(N−40)/4 |
| 120 | 70.0 °F | 21.1 °C | Field cricket: 50+(N−40)/4 |
| 160 | 80.0 °F | 26.7 °C | Field cricket: 50+(N−40)/4 |
| 240 | 100.0 °F | 37.8 °C | Field cricket: 50+(N−40)/4 |