In aviation terms weather information is obviously much clearer and much more detailed. Like Jwenting said, we would receive weather info in terms of broken and overcast - we even get the ceiling and the type(s) of clouds hovering over us.
But what about for the common folk who may not be all that schooled in weather? Generally and assumingly, yes, partly sunny would mean more than sun than clouds and partly cloudy would mean more clouds than sun. But is this really the case when our local weather person tells us these terms?
Its better to be on the ground wishing you were in the air than be in the air wishing you were on the ground. Fly safe!