What is the difference between partly cloudy and mostly sunny?

Believe it or not, there is a difference. It relates to the average amount of cloud cover expected. Would you believe partly sunny means more cloud cover than partly cloudy? Can be confusing to the public...mostly sunny means more sun than partly cloudy does, while partly sunny means more clouds than partly cloudy does. Anyway, from least cloud cover to most, the scale is: sunny, mostly sunny, partly cloudy, partly sunny, mostly cloudy, cloudy. Mostly sunny means more sun than clouds, partly sunny means more clouds than sun, and partly cloudy generally means an equal amount of clouds and sun.