Probability of precipitation used in weather forecasts; the likelihood (usually given as a percentage) that rain or snow will occur during a specified period.
明日の降水確率は70％なので傘を持って行ったほうがいい。
The chance of precipitation tomorrow is 70%, so you should take an umbrella.
午前と午後で降水確率が違うから、出かける時間を考えよう。
The chance of rain differs between morning and afternoon, so let's consider what time to go out.
テレビの天気予報で降水確率をチェックした。
I checked the precipitation chance on the TV weather forecast.