yeoreumeneun undonghwaboda saendeureul deo jaju sinjiman, bi oneun nareneun an sineo.

Korean often leaves out the subject when it is clear from context.

So this sentence does not explicitly say I, but in isolation it will often be understood as I. Depending on context, it could also refer to we, you, or someone already being talked about.

The same omitted subject applies to both clauses:

• 여름에는 ... 신지만
• 비 오는 날에는 안 신어

So the person doing both actions is the same understood subject.

에는 is 에 + 는.

• 에 marks time: in summer, on a day
• 는 adds topic or contrast

So 여름에는 means something like in summer, as for that time... and 비 오는 날에는 means on rainy days, as for those days...

Here, 는 helps create a contrast:

• in summer → sandals are worn more often
• on rainy days → they are not worn

If you used just 여름에 and 날에, the sentence would still make sense, but it would sound less contrastive.

No. Here, 보다 is not the verb to see.

After a noun, 보다 is a comparison particle meaning than.

So:

• 운동화보다 = than sneakers
• 운동화보다 샌들을 더 자주 신다 = wear sandals more often than sneakers

A very common comparison pattern is:

A보다 B를 더 + adjective/adverb + verb
= more B than A

Because 샌들 is the direct object of 신다.

The verb 신다 means to wear on the feet, so the thing being worn takes the object marker:

• 샌들을 신다 = to wear sandals
• 운동화를 신다 = to wear sneakers

Since 샌들 ends in a consonant sound, it takes -을.
If a noun ended in a vowel, it would take -를 instead.

• 더 = more
• 자주 = often, frequently

Together, 더 자주 means more often.

It is comparing frequency, not quantity.
So the idea is not I wear more sandals, but I wear sandals more often.

In this sentence, the comparison is between:

• wearing sneakers
• wearing sandals

Korean uses different verbs for wearing depending on the item.

신다 is used for things worn on the feet, such as:

• shoes
• sneakers
• sandals
• socks
• stockings

So 샌들을 신다 is the normal way to say to wear sandals.

Some other common wearing verbs are:

• 입다 for clothes
• 쓰다 for hats
• 끼다 for rings, gloves, glasses
• 메다 for a backpack
• 차다 for a watch or belt

So even though English uses wear for all of these, Korean chooses different verbs by category.

-지만 means but or although.

It connects two clauses and shows contrast.

So:

• 신지만 = (I) wear ..., but ...

In this sentence, the contrast is:

• sandals are worn more often in summer
• but on rainy days, they are not worn

It is a very common connector in Korean:

• 좋지만 = it's good, but...
• 가지만 = go, but...
• 먹지만 = eat, but...

비 오는 날 literally means a day when rain comes/falls, which is naturally a rainy day or a day when it rains.

Here is the structure:

• 비 오다 = to rain
• 오다 → 오는 = noun-modifying form
• 날 = day

So 오는 is modifying 날.

This noun-modifying pattern is very common:

• 제가 읽는 책 = the book I read / am reading
• 사람이 사는 집 = a house where people live
• 비 오는 날 = a day when it rains

Also, 비 오는 날 is a very common weather expression. You may also hear 비가 오는 날, but 비 오는 날 is completely natural.

Because Korean often omits words that are already understood from context.

In the first clause, 샌들을 has already been mentioned. In the second clause, repeating it is unnecessary, so it is dropped.

So 안 신어 here means:

• (I) don’t wear (them)

The omitted object is understood to be sandals.

This kind of omission is extremely common in Korean conversation and writing.

Both are negative forms, but 안 신어 is the shorter one.

• 안 신어 = short negation
• 신지 않아 = long negation

In many everyday situations, the short form with 안 is very common and natural.

So:

• 안 신어 = don’t wear
• 신지 않아 = don’t wear

They are very similar in meaning here. The short form usually feels lighter and more conversational.

신어 is the casual/plain conversational form.
신어요 is the polite form.

So the sentence is written in an informal style, suitable for:

• talking to a friend
• casual conversation
• diary-style writing
• examples in plain speech

Compare:

• 안 신어 = casual
• 안 신어요 = polite

The first clause also matches this style:

• 신지만 and then the sentence finishes casually with
• 안 신어

It describes a general habit or tendency, not necessarily what the speaker is doing at this exact moment.

Korean present-tense forms often express:

• habits
• general facts
• repeated actions
• usual behavior

So here the idea is:

• in summer, sandals are worn more often
• on rainy days, they are not worn

It is not limited to right now today.