agroclimatic index

A measure or indicator of an aspect of the climate that has specific agricultural significance.

Examples of an agroclimatic index are average length of growing season (period between average last and first freezing temperature dates), average growing degree-days or heat units in a growing season, average total chill hours or chill units, and average evapotranspiration.

Any function of time f(t) is periodic with period t if f(t) = f(t + τ) for all times t, where τ is the smallest number for which this equality holds.