May 22, 2020

What is the difference between partly sunny and partly cloudy?

Twice today I was asked about the difference between partly cloudy and partly sunny.   And that inquiry is one of the most frequent I get, for reasons I do not understand.

OK...let's settle this for once and for all.

Here is an image of a partly cloudy sky:

And here is an image of a partly sunny sky:

They are the same..... during the day, partly cloudy and partly sunny denote exactly the same thing:  a sky with between 3/8 and 5/8 coverage of clouds.   Obviously, partly cloudy would be a better choice at night.

Mostly cloudy  is 5/8 to 7/8 coverage, while mostly sunny indicates 1/8 to 3/8 coverage during the day.

Now, a harder one.   What does it mean to have a sky obscured?   Is it the same as an overcast sky?

The answer to the second question is NO--they are not the same.

The sky is obscured when you can not see the sky, when you are in middle of cloud or smoke or dust storm.  Here are two examples of an obscured sky, one from smoke and the other from low clouds/fog:

An overcast sky is when the entire sky is covered by clouds or smoke, but you are not in them.  You can see the base (bottom part) of the clouds or smoke.  Here is an example:

With this knowledge, you can amaze your friends at the next cocktail party.... whenever cocktail parties start again. 


  1. It's good to give people a choice: Do you want a peanut butter and jelly sandwich, or would you rather have a jelly and peanut butter sandwich? (At 3 my daughter would eat the first, but not the second.) Would you like to sit in the waiting room, or wait in the sitting room? ;-)

  2. A few of the reporting stations on NOAA weather radio--for some unexplained reason--report sunny or partly sunny conditions at night,instead of "fair" or "partly cloudy".

  3. To me, partly cloudy "sounds like" more sun than clouds, and partly sunny "sounds like" more clouds than sun.

  4. Funny, Cliff!

    Reminds me of that old song "potAto, potato, tomAto, tomato . . . let's call the whole thing off . . .

    Glad you're having fun with weather questions.

  5. Ha! I thought the typical Seattle forecast was: Rain, with a chance of clouds.

  6. My accuweather app tells me when it's 'sunny and beautiful' out. Never sure when it's just sunny without being beautiful or if it can be anything else with beautiful. I'm on the ferry right now and its cloudy and beautiful as far as I can tell.

  7. I read a good one the other day: The birth of the cocktail hour can be dated precisely, 1 minute after midnight on Jan 1, 1933, when prohibition ended. :)

  8. Almost every day here (coastal N. Cal.) the forecast includes either 'partly sunny' or 'partly cloudy', and I wonder . . . Now I know - Thanks!

  9. I understand that this thing called SAD...seasonal affective due, in our the overcast situation. The rain is not the culprit!...Both Seattle and London have similar, frequently cloudy weather....and the suicide rates are similar!..I knew a younger neighborhood couple, from Kansas, who moved here several years ago, for job situations. But they gave up on our weather (and the liberal politics!), and moved back to Topeka!!...Being born and raised here, I guess I just do not know better, and accept our weather situation.

  10. Ok, so what I dislike is what I call ambivalent skies. Right now, 5 24 2020 at 9:41 am, the sky is white with indistinguishable clouds. They are not thick enough to obscure the sun, so they are glaring white and you can pinpoint the sun (behind these wimpy clouds) where the glare is most intense...that's all I have to say about that!

  11. Well now you know, but I STILL don't know. There must be a difference amongst those who do the reporting. I mean what do they do, flip a coin? Take turns getting to choose "partly cloudy" or "partly sunny"? Does the employee of the month get to choose? We're still missing something here.

  12. It sounds like the good ol glass half empty vs glass half full argument.


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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