Accumulating Degree Units: Changing the Convention Changes the Record

Accumulating Degree Units: Changing the Convention Changes the Record; illustrative quantitative diagram

Image use and attribution

Make a controlled comparison

Daily values should be added only when their unit and convention match. Switching the base, cap or treatment of minimum temperature halfway through a season produces a different series. The accumulated arithmetic alone does not validate a development-stage or harvest prediction.

GDU Calculator — Growing Degree Units makes the stated relationship reproducible. It cannot supply missing product information, identify a representative sample or establish a suitable site-specific management decision.

Change one input at a time

The table varies Daily maximum air temperature (°C) around the illustrative starting value while retaining the other assumptions. These are sensitivity scenarios, not a measured range or recommended settings.

Browse Biology calculators and its Gardening and crops calculators section when another measurement is needed. A related tool may use a different denominator or physical basis.

Keep the interpretation within scope

Keep Daily maximum air temperature (°C) with the selected output in the comparison record. The three alternatives do not identify which input applies to a particular site or product. A justified new observation should be recorded as new evidence, rather than choosing an input merely because its result looks convenient.

A related quantity

Daily Light Integral Calculator addresses a related part of the task. Check its own input definition before carrying a number across.

Continue with Growing Degree Units: Identify the Base and Temperature-Bounding Method for the other part of this measurement question.

Return to GreenCalc for other subjects. Keep raw observations, chosen assumptions and calculated quantities identifiable so a later revision does not overwrite the basis of the original record.

By GreenCalc · Updated 2026-11-06