Forecast terminology

[wrongway]

Hi John, long time reader first time poster here. I've always wondered what the difference would be in the terminology "partly cloudy" and "mostly sunny" since they would seem to mean the same thing. At first I thought that "partly cloudy" would only be used at night, but I still see it used for daytime forecasts.

Thanks, Doug.

 

[jd]

I am sure that the NWS has guidelines for how they use the term, but I do not know exactly what they are.

For me, sunny means less than 10% cloud cover, mostly sunny around 11-25% cloud cover, partly cloudy around 26-40% cloud cover, partly sunny around 41-65% clouds, mostly cloudy around 66-90% cloud cover.

-John