partly cloudy

1. In U.S. climatological practice, the character of a day's weather when the average cloudiness, as determined from frequent observations, has been from 0.4 to 0.7 for the 24-hour period.

Compare clear, cloudy.

1. In popular usage, the state of the weather when clouds are conspicuously present but do not completely dull the day or the sky at any moment.
   In weather forecast terminology, this term may be used when the expected cloudiness is from about 0.3 to 0.6.

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.

1. The product of a distance and another parameter.