You would think we never use "skies" since there's only one sky, but I've heard it often enough that I often want to say "skies" rather than "sky". The problem is that I never gave much thought about it, so I have no idea why I even want to do that.

When do we say “skies” instead of “sky”?

  • 1
    Could you give an example to when someone has used "skies"? I've heard says such as "sky's the limit" but can't think of one which uses "skies"
    – Matthew
    Commented Jan 30, 2019 at 14:42
  • 1
    @Matthew - The chorus to Irving Berlin's 1926 song comes to mind.
    – J.R.
    Commented Jan 30, 2019 at 14:55
  • 1
    I like blue skies. Commented Jan 30, 2019 at 19:19

6 Answers 6


Wordnik gleans from a few dictionaries and puts all the definitions on one page. Some of the definitions of sky found there include:

sky (n.) n. The appearance of the upper atmosphere, especially with reference to weather. Often used in the plural: Threatening skies portend a storm.

sky (n.) The apparent arch, or vault, of heaven, which in a clear day is of a blue color; the heavens; the firmament; -- sometimes in the plural.

(emphasis added)

These entries show that a plural form is acceptable, as you've noticed; however, they don't delve into when might be the right time to use the word skies. The best I could find about that was in Cambridge:

skies [ plural ] the sky in a particular state or place:
For weeks we had cloudless blue skies.
We're off to the sunny skies of Florida.

Near as I can tell, it's okay to use the plural form when you are referring to the weather, or to the sky in a particular state or place. That said, the plural wouldn't be mandatory in these cases (although you may have to tweak the wording); these sentences are also grammatical and idiomatic:

  • A threatening sky portends a storm.
  • For weeks we saw a cloudless blue sky.

As for this one:

  • We're off to the sunny sky of Florida.

I think skies sounds more natural there, but I don't think I can deem the singular as ungrammatical.

  • So either one of them is fine in any situation?
    – aLex
    Commented Feb 6, 2019 at 17:57
  • @puff - I didn't say that, and I think it's more complicated than that. I think there's often a difference in tone, too. In many cases, the plural may sound more "poetic".
    – J.R.
    Commented Feb 6, 2019 at 19:31

skies can refer to the sky over a period of time during which the sky changes.

Tomorrow we can expect mostly cloudy skies.

The underlying idea, I think, is of the changing sky.

The plural is also used with the ocean:

We sailed to warmer waters.

where the underlying idea is that the ocean has qualities that vary as one moves over the watery surface of the planet, such that there are discrete regions of sea.


You usually say the sky. When sky is used with an adjective, use a… sky. You can also use the plural form skies, especially when you are thinking about the great extent of the sky Oxford Advanced Learner's Dictionary 9th edition © Oxford University Press, 2015

  • This adds nothing to the existing answers
    – Chenmunka
    Commented Mar 12, 2020 at 18:00
  • @Chenmunka ... and parts of it are wrong: When sky is used with an adjective, use a… sky. "the blue sky" is perfectly idiomatic.
    – CJ Dennis
    Commented Mar 13, 2020 at 4:37

It is also an aviation term.

As in the Open Skies Treaty. This has to do with political or administrative clearance, something that as of today, 2020 March 12, is in the news due to travel restrictions related to the COVID-19 virus. (Notice how neutral I stayed on that issue.)

Also as in a pilot being friendly and wishing you clear skies. This refers to both good flying weather clear of clouds, and little to no traffic, meaning clear flying. (The article is about proposed changes in the language pilots use. These changes are intended to keep planes from hitting each other.)


Today the sky over London may be cloudy but the same sky over Mumbai may be clear. If you are in London you will say the sky is cloudy while being in Mumbai I will say it is clear over here. Similarly for a pilot "weather conditions" are different for every 20 kilometres, if he finds a clear weather everywhere, he will inform the authority "the skies are very clear".

Moreover, a poet can describe Egypt as "Egypt is a place of endless blue skies and deserts," just to make you feel the vastness and beauty of the place.


The sky is not always the same.

When you talk about "skies" you are comparing different instances of the big thing above you, and emphasizing its changing characteristics.

A night sky is beautiful and full of stars. A cloudy sky is grey. A clear sky is nice for pilots. In a sense, those are all different "skies" even though the expanse above us is always the same "sky."

For a safe option, just always use "sky." When you are comparing different sky-states, you can use "skies" to either emphasize the differences or to emphasize a common characteristic across time ("a week of grey skies").

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