Learn Hardcore Korean: yeoreumeneun biga manhi wayo.

-에 marks a time or place (“in summer”), and 는 turns that phrase into the topic of the sentence. Together -에는 means “as for in summer,” setting 여름 as what we’re talking about.

Can I omit 는 and just say 여름에 비가 많이 와요?

Yes. 여름에 비가 많이 와요 still means “It rains a lot in summer,” but without 는 it sounds more neutral and less topicalized. Adding 는 emphasizes or contrasts “summer” against other seasons.

Why is 비가 used instead of 비는?

가 marks the subject when you’re presenting new information. Using 비는 would make “rain” the topic or imply a contrast (e.g. “As for rain…”). Here we simply state that rain does something (rains heavily), so 가 is appropriate.

What kind of word is 많이, and what does it modify?

많이 is an adverb meaning “a lot” or “much.” It modifies the verb 와요, telling us how the rain comes (i.e. heavily, frequently, in large amounts).

Why does the verb 와요 appear at the end of the sentence?

Korean follows a Subject-Object-Verb (SOV) order. Even though 비가 많이 is an adverbial phrase, the verb still comes last in the sentence structure.

Why is 오다 used for “rain” instead of 내리다?

In everyday Korean, rain is described as “coming”: 비가 오다. 내리다 (“to descend”) can also be used (비가 내리다), but it’s more literary or formal and less common in casual speech.

What politeness level is 와요?

와요 uses the -아/어요 polite informal ending. It’s respectful enough for strangers or acquaintances in everyday conversation but not as formal as 옵니다.

Why do we attach 가 after 비 and not 이?

Korean has two subject particles: 가 and 이. You use 가 after a noun ending in a vowel (like 비), and 이 after a noun ending in a consonant.

Could I say 많은 비가 와요 instead of 비가 많이 와요?

You could, but 많은 비가 와요 sounds odd because 비 is generally uncountable. Koreans prefer using the adverb 많이 to quantify how much it rains, rather than treating 비 as a countable noun.

Does 여름에는 비가 많이 와요 describe a single event or a habitual fact?

The simple present tense (-아요) in Korean often expresses general truths or habitual actions. Here it means “It tends to rain a lot in summer,” not just one isolated rainstorm.