What's the difference between cloudy and cloudy weather forecast?

The state of the sky is determined by the amount of clouds in the sky and the intensity of sunlight.

There are four situations: sunny, partly cloudy, cloudy and cloudy.

Sunny days: the sky is cloudless, or the medium and low clouds are less than 1%, and the high clouds are below 40%.

Partly cloudy: there are 1% ~ 30% medium-low clouds or 40% ~ 50% high clouds in the sky.

Cloudy: There are 40% ~ 70% medium-low clouds or 60% ~ 10% high clouds in the sky.

Cloudy day: It is dark, covered with clouds, or slightly cloudy, but it still feels dark.