What's the difference between "partly cloudy" and "partly sunny"?

June 11, 2008 8:22:53 AM PDT
Michelle of Newtown, PA asks: Is there a scientific definition or threshold to determine whether to call a forecast "mostly sunny" versus "Partly cloudy"?

Erica's Answer:

It's really just personal preference. The person writing the forecast chooses how they want to describe the day's weather. For instance, if we've had several cloudy days, but we have a day coming up in the forecast in which we'll see a good amount of sun, I'll say "Partly Sunny" for that day. That way, I'm emphasizing how our weather will change- we'll see more sun.

- Erica