karendaa wo miru tabi ni, tugi no syukuzitu ga tanosimi ni narimasu.

たびに means every time.

So:

• カレンダーを見るたびに = every time I look at the calendar

It describes something that happens repeatedly whenever the first action happens.

A useful pattern is:

• dictionary form verb + たびに = every time someone does that verb

Examples:

• 本を読むたびに = every time I read a book
• 彼に会うたびに = every time I meet him

Because たびに normally attaches to the plain/dictionary form of a verb.

So:

• 見るたびに = every time I look

You do not say:

• 見ますたびに ✘

This is a common grammar pattern, even when the overall sentence is polite at the end.

So the sentence mixes:

• a plain-form verb inside the grammar pattern: 見るたびに
• a polite ending: なります

That is completely normal in Japanese.

Because 見る is a transitive verb, and the thing being looked at is marked by を.

So:

• カレンダーを見る = to look at the calendar

Here, カレンダー is the direct object of 見る.

In たびに, the に is part of the fixed expression. It is not something you should try to translate word-by-word in a simple way every time.

It is best to learn たびに as one grammar item meaning:

• whenever
• every time

So:

• 見るたびに = every time I look
• 行くたびに = every time I go

次の means next.

So:

• 次の祝日 = the next holiday

It comes from:

• 次 = next
• の = links the noun 次 to another noun

This is a very common structure:

• 次の駅 = the next station
• 次の日 = the next day
• 次のページ = the next page

These words are related, but they are not the same.

• 祝日 = a national/public holiday
• 休日 = a day off, holiday, non-working day
• 休み = a break, rest, time off, holiday in a broad everyday sense

In this sentence, 祝日 is used because it specifically means an official holiday on the calendar.

So 次の祝日 gives the feeling of looking ahead to the next official holiday date.

Because 楽しみになる is built around 楽しみ as a state, and the thing you look forward to is often marked with が.

So:

• 次の祝日が楽しみになる = to come to look forward to the next holiday

This does not mean the holiday is the subject in the English sense of the holiday becomes excited.
Rather, 次の祝日 is the thing that is anticipated.

Compare:

• 旅行が楽しみです = I’m looking forward to the trip
• 週末が楽しみです = I’m looking forward to the weekend

Japanese often marks the thing you are excited about with が.

Here, 楽しみ means something like:

• a pleasure
• something to look forward to
• anticipation

The pattern Noun + に なる means to become that state.

So:

• 楽しみになる = to become something one looks forward to
• more naturally in English: to start looking forward to it

In this sentence:

• 次の祝日が楽しみになります = I start looking forward to the next holiday or = the next holiday becomes something I look forward to

This is a very natural Japanese expression.

Good question. These are related but different.

楽しみにする

This means to look forward to something in a more intentional or direct sense.

• 旅行を楽しみにしています = I’m looking forward to the trip

楽しみになる

This means to come to look forward to something or for something to become exciting/anticipated.

• 旅行が楽しみになる = the trip becomes something I look forward to

In this sentence, the idea is:

• every time I look at the calendar, the next holiday becomes more and more something I look forward to

So なる fits the sense of a change in feeling.

Because in Japanese, the politeness of the sentence is usually shown at the end.

So it is normal to have:

• 見る in plain form inside a grammar structure
• なります as the polite final verb

This is extremely common.

Compare:

• 日本に行くと、うれしいです。
• 本を読むたびに、勉強になります。

The sentence is polite because the final predicate is polite.

The subject is omitted because Japanese often leaves it out when it is understood from context.

In natural English, you would probably translate it as:

• Every time I look at the calendar, I start looking forward to the next holiday.

But Japanese does not need to say 私は here unless there is a reason to emphasize it.

So the sentence naturally leaves the person unstated.

Not really. That would be too literal and would miss the actual Japanese meaning.

Here, 楽しみ does not just mean fun. It often means:

• something to look forward to

So:

• 次の祝日が楽しみになります

means more like:

• the next holiday becomes something I look forward to
• I start looking forward to the next holiday

This is a very important nuance.

You could, but the meaning changes.

• カレンダーを見るとき = when I look at the calendar
• カレンダーを見るたびに = every time I look at the calendar

とき just gives a time frame.
たびに emphasizes repetition: the feeling happens each time without exception.

So たびに is the better choice here.

The comma is mainly for readability and natural pacing.

• カレンダーを見るたびに、次の祝日が楽しみになります。

It separates the every time... part from the main clause.

In many cases, Japanese commas are more flexible than English commas, so the sentence could still be understood without it. But with the comma, it is easier to read.

A casual version would be:

• カレンダーを見るたびに、次の祝日が楽しみになる。

The only change is:

• なります → なる

Everything else can stay the same.

So:

• なります = polite
• なる = casual/plain

They are related, but they are used differently.

• 楽しい = fun, enjoyable
• 楽しみ = pleasure, anticipation, something to look forward to

Examples:

• 旅行は楽しい。 = The trip is fun.
• 旅行が楽しみ。 = I’m looking forward to the trip.

In this sentence, 楽しみ is correct because the speaker is anticipating the next holiday, not saying the holiday itself is fun right now.