Degree Day Calculator

Accumulated degree days from daily temperature data using the single-sine method for predicting pest development stages.

Daily high temperature (°F)

Daily low temperature (°F)

Base development threshold (°F)

Upper cutoff temperature (°F)

Number of days

Tab to move between fields

Degree-days per day

Total accumulated DD

280

Average daily temperature (°F)70

Effective temperature above base (°F)20

Estimated pest generations0.56

Days to first generation25

How to Use This Calculator

Enter Daily high temperature (°F), Daily low temperature (°F), and Base development threshold (°F).
Set Upper cutoff temperature (°F) and Number of days.
Review Degree-days per day and Total accumulated DD.
Use Average daily temperature (°F) and Effective temperature above base (°F) to inform your decision.

How the result changes with Base development threshold (°F)

Base development threshold (°F)	Degree-days per day	Total accumulated DD
10	60	840
35	35	490
65	7.54	105.59
90	0	0

Daily high temperature (°F): Maximum daily temperature recorded or forecasted.
Daily low temperature (°F): Minimum daily temperature recorded or forecasted.
Base development threshold (°F): Lower developmental threshold for the target pest (e.g., 50°F for codling moth, 46°F for corn earworm).
Upper cutoff temperature (°F): Upper developmental threshold where pest growth ceases (commonly 86-100°F).
Number of days: Duration of the monitoring window in days.

Degree-days per day: Single-sine accumulated degree-days for one day at these temperatures.
Total accumulated DD: Total degree-days over the full monitoring window.
Average daily temperature (°F): Simple average of daily high and low.
Effective temperature above base (°F): Average temperature minus the base threshold.
Estimated pest generations: Approximate number of pest generations (assuming ~500 DD per generation).
Days to first generation: Estimated days until the first pest generation completes at this rate.

Identify Input Parameters
4 parameters
Daily high temperature (°F) = 85, Daily low temperature (°F) = 55, Base development threshold (°F) = 50, Upper cutoff temperature (°F) = 100 = 5 input(s) provided
Calculate Degree-days per day
Degree-days per day
20 = 20
Calculate Total accumulated DD
Total accumulated DD = ddPerDay * days
280 = 280
Calculate Average daily temperature
Average daily temperature = (hi + lo) / 2
70 = 70
Calculate Effective temperature above base
Effective temperature above base = Math
20 = 20