ame no hi ha kega wo sinai you ni ki wo tukemasu.

Here, 日 is read ひ, not にち.

So:

• 雨 = rain
• 日 = day
• 雨の日 = a rainy day / days when it rains

Literally, it is rain’s day, but in natural English it means a rainy day or on rainy days.

の connects nouns. It often works like of or shows a descriptive relationship.

So:

• 雨の日 = day of rain → rainy day

This is a very common pattern in Japanese:

• 夏の日 = summer day
• 休みの日 = day off
• 日本の車 = Japanese car / car of Japan

In this sentence, 雨の日 is just a noun phrase meaning rainy days.

は marks the topic of the sentence.

So 雨の日は means something like:

• As for rainy days, ...
• On rainy days, ...

The speaker is setting rainy days as the situation being talked about.

This is very natural in Japanese when introducing a general condition or context.

That is a very common question.

Both に and は can appear with time-related expressions, but they do different jobs:

• に marks a specific time point
• は marks the topic or contrast

In this sentence, the speaker is not just saying at/on rainy days. They are saying something more like:

• When it’s a rainy day, I’m especially careful...
• As for rainy days, ...

So は is used to frame the sentence.

Also, time expressions like this often do not need に at all. Japanese commonly says:

• 日曜日は勉強します = As for Sundays / On Sundays, I study

You could also say 雨の日には, which adds a bit of emphasis or contrast, but 雨の日は is perfectly natural.

けが means injury or hurt as a noun.

The expression けがをする literally means to do/receive an injury, but in natural English it means:

• to get injured
• to get hurt

That is why を is there: けが is the object of する in this fixed expression.

So:

• けが = injury
• けがをする = to get injured

In the sentence, it becomes negative:

• けがをしない = not get hurt / not get injured

In this sentence, ように means something like:

• so that
• in order that
• with the aim of

So:

• けがをしないように = so that I don’t get hurt / in order not to get hurt

This pattern is very common:

• 忘れないようにメモします = I make a note so that I won’t forget.
• 遅れないように早く出ます = I leave early so that I won’t be late.

So here, ように connects the goal/result to the action of being careful.

Because the speaker wants to avoid injury.

• けがをする = get hurt
• けがをしない = not get hurt

Then:

• けがをしないように気をつけます = I am careful so that I do not get hurt.

If you said けがをするように, it would mean so that I get hurt, which is the opposite of the intended meaning.

Literally:

• 気 = spirit / mind / attention
• をつける = attach / apply

But as a set expression, 気をつける means:

• to be careful
• to watch out
• to take care

So 気をつけます is the polite form of 気をつける.

In this sentence:

• けがをしないように気をつけます
• I’m careful not to get hurt
• I take care not to get injured

It breaks down like this:

• 雨の日は = as for rainy days / on rainy days
• けがをしないように = so that I don’t get hurt
• 気をつけます = I am careful

So the overall structure is:

[Time/topic] + [goal to avoid something] + [be careful]

Natural English translations include:

• On rainy days, I’m careful not to get hurt.
• I take care not to get injured on rainy days.

Usually it sounds like a general habit or a regular attitude:

• On rainy days, I’m careful not to get hurt.

That is because:

• 雨の日は often has a general meaning, like when it’s rainy or on rainy days
• 気をつけます in non-past form can express a habit, rule, or general practice

If the speaker wanted to refer to one specific rainy day, the context would usually make that clear.

The subject is omitted, which is very normal in Japanese.

From context, the sentence usually means:

• I am careful not to get hurt on rainy days.

Japanese often leaves out subjects like I, you, or we when they are obvious from the situation.

So even though 私 is not written, listeners naturally understand it if the speaker is talking about their own behavior.

Yes, in casual Japanese you may sometimes hear けがしない. However, けがをする is the standard and very common form, so けがをしないように is completely natural and safe to learn.

For learners, it is best to remember:

• けがをする = to get hurt

That pattern will work well in most situations.