weather term
Precipitation
Any form of water, liquid or frozen, that falls from clouds to the ground, including rain, snow, sleet and hail.
Forecasts often describe precipitation using two related but different numbers: the probability of precipitation, which is the chance that measurable rain or snow falls at a given point, and the expected amount, usually given in millimetres or inches. A high probability doesn't necessarily mean heavy rainfall, and a low probability doesn't rule it out entirely; the two numbers are best read together rather than in isolation.
Read the full article: How Rain Probability Actually Works.