Learn Hardcore Japanese: kumori no hi ha zinzya ga sizuka desu.

曇り (くもり) by itself means “cloudiness” or “the state of being cloudy.” To say “cloudy day,” Japanese attaches 日 (day) and links them with の, making 曇りの日 (“day of cloudiness”). This pattern (XのY) is common: e.g. 雨の日 (“rainy day”), 晴れの日 (“sunny day”).

What’s the function of の between 曇り and 日?

Here, の is the genitive/attributive particle that connects two nouns. It turns 曇り (“cloudiness”) and 日 (“day”) into one compound noun meaning “cloudy day.” It’s like the English “day of X.”

Why is は used after 曇りの日 instead of に for time?

は marks 曇りの日 as the topic: “As for cloudy days…” It sets the time frame and often implies contrast or generalization. You could use に to mark time (“on cloudy days”)—曇りの日に神社が静かです—but that lacks the topical nuance of は.

Why is が used after 神社 instead of は?

が marks 神社 as the grammatical subject, focusing on “shrines” experiencing the state of being quiet. If you said 神社は静かです, you’d turn “shrines” into the broader topic and might sound like you’re making a general statement or contrast. Both are possible, but with slightly different nuance.

What part of speech is 静か, and why is です attached?

静か (しずか) is a na-adjective (形容動詞). In polite speech, na-adjectives need the copula だ/です to form a predicate: 静かです (“is quiet”). In casual speech, you’d use 静かだ.

How would you say this sentence in casual/informal Japanese?

Swap です for だ:
• 曇りの日は神社が静かだ。
In very casual speech, you might even drop だ, but that’s colloquial.

Does 神社 here refer to one shrine or many shrines? How do you express plurality?

Japanese nouns aren’t marked for number. 神社 can mean “a shrine,” “shrines” or “shrine(s)” depending on context. Here it generally means “shrines” in general. If you need to be explicit, you’d add a quantifier (e.g. 二つの神社 “two shrines”).

Can I reorder the sentence to 神社が曇りの日は静かです?

No—Japanese prefers time/topic phrases like 曇りの日は at the beginning. 神社が曇りの日は… breaks the natural flow and sounds awkward.

What if I say 曇りの日の神社は静かです instead?

That changes the structure: 曇りの日の神社 uses の to modify 神社, meaning “the shrine on a cloudy day.” It feels like you’re talking about one specific shrine tied to “cloudy day,” rather than stating that “shrines are quiet on cloudy days” in general.

How do you turn this into a question: “Are shrines quiet on cloudy days?”

Add the question particle か at the end:
• 曇りの日は神社が静かですか？