Calculator · climate
Growing degree-days calculator
Accumulate a single day of growing degree-days from daily temperatures and a base temperature.
Result
Enter values to see a result.
Formula & assumptions
Growing degree-days (average method)
formula v1.0.0 · calc v1 · reviewed 2026-07-12GDD = max(0, (T_max + T_min) ÷ 2 − T_base)
Applies to: Base-temperature GDD accumulation for a single day.
Assumptions
- Simple average method; daily mean is the average of max and min.
Limitations
- No upper threshold; base temperature is crop-specific.
Sources: University of California Agriculture and Natural Resources (UC ANR) (opens in a new tab)
Growing degree-days (with upper cutoff)
formula v1.0.0 · calc v1 · reviewed 2026-07-12GDD = max(0, (min(T_max, cap) + min(T_min, cap)) ÷ 2 − T_base)
Applies to: Crops whose development plateaus above an upper threshold.
Assumptions
- Horizontal cutoff: temperatures above the cap are set to the cap.
Limitations
- The horizontal-cutoff method is one of several; choose the model your crop uses.
Sources: University of California Agriculture and Natural Resources (UC ANR) (opens in a new tab)
About this tool
- Base and cutoff temperatures are crop-specific; this computes one day and does not infer crop stage without a validated crop model.
Educational reference — not a prescription
- These calculators are for education and reference. The quality of any result depends entirely on the accuracy of the values you enter.
- Local agronomic conditions, legal requirements, product labels, and professional advice may override a general calculation.
- Results are not pesticide, fertilizer, irrigation, or veterinary prescriptions, and are not a substitute for advice from a qualified agronomist or your local extension service.