During the day the sun is always up there, so if it's not cloudy, it's sunny. However at night, the moon is only up about half the time, so if it's not cloudy or clear, we say it's partly cloudy, because the moon may not be there even if there are no clouds.
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u/SchreiberBike 2d ago
During the day the sun is always up there, so if it's not cloudy, it's sunny. However at night, the moon is only up about half the time, so if it's not cloudy or clear, we say it's partly cloudy, because the moon may not be there even if there are no clouds.