אני לא רגיל לקום כל כך מוקדם ביום שלישי.

Because in Hebrew, the verb to be is usually omitted in the present tense.

So:

• אני רגיל = I am used to / I am accustomed to
• אני לא רגיל = I am not used to

Literally, Hebrew says something like I not used.

In the past and future, Hebrew does use forms of to be or other full verb structures, but in the present it is normally left out.

Here רגיל means used to, accustomed to, or in the habit of.

So אני לא רגיל לקום... means:

• I’m not used to getting up...
• I’m not accustomed to getting up...

A very important point: this does not mean I usually don’t get up.

Compare:

• אני לא רגיל לקום מוקדם = I’m not used to getting up early
• אני בדרך כלל לא קם מוקדם = I usually don’t get up early

Those are different ideas.

Because רגיל agrees with the speaker.

In this sentence, the speaker is grammatically masculine singular:

• אני לא רגיל = said by a male speaker
• אני לא רגילה = said by a female speaker

If you were speaking to or about other people, the form would change too:

• אתה לא רגיל
• את לא רגילה
• אנחנו לא רגילים / רגילות

Hebrew adjectives usually agree in gender and number.

Because Hebrew commonly uses the pattern:

רגיל + ל + infinitive

That is how Hebrew says used to doing something.

So:

• רגיל לקום = used to getting up
• רגילה לעבוד בלילה = used to working at night
• רגילים לאכול מאוחר = used to eating late

The infinitive לקום already begins with ל־, so you do not add another separate ל before it.

לקום literally means to get up, to rise, or sometimes to stand up, depending on context.

In this sentence, because we are talking about time in the morning, it means:

• to get up
• sometimes naturally translated as to wake up, though the more exact verb for wake up is להתעורר

So:

• לקום מוקדם = to get up early
• להתעורר מוקדם = to wake up early

In everyday English, both may sound natural depending on context, but in Hebrew they are not exactly the same verb.

כל כך means so, so much, or that in the sense of degree.

Here:

• כל כך מוקדם = so early

It strengthens the word that follows it.

Examples:

• כל כך טוב = so good
• כל כך מהר = so fast
• כל כך קשה = so difficult

So the sentence is not just early, but so early.

Because Hebrew often uses an adjective form where English would use an adverb.

In English, we say:

• early as an adverb in get up early

In Hebrew, מוקדם is also used naturally in this kind of adverbial role:

• לקום מוקדם = to get up early
• לבוא מאוחר = to come late
• לנסוע מהר = to travel fast

So even though מוקדם looks like an adjective, in this sentence it functions very naturally as early.

ביום שלישי means on Tuesday.

Breakdown:

• ב־ = in / on
• יום = day
• שלישי = third

Hebrew names weekdays numerically, so יום שלישי is literally third day, which is Tuesday.

So:

• ביום ראשון = on Sunday
• ביום שני = on Monday
• ביום שלישי = on Tuesday

This is a very normal way to express days of the week.

Because יום שלישי is being used as the normal name of the weekday, Tuesday, not as the third day in some special sequence.

So:

• ביום שלישי = on Tuesday
• ביום השלישי would more likely mean on the third day

That is an important difference. Hebrew weekday names often look like ordinal numbers, but when used as weekday names they usually appear without ה־.

It can depend on context.

In many situations, ביום שלישי can mean:

• on Tuesday = one specific Tuesday
• or sometimes on Tuesday(s) if the broader context is habitual

But if you want to say every Tuesday or on Tuesdays more clearly, Hebrew often uses:

• בימי שלישי = on Tuesdays / every Tuesday

So:

• אני לא רגיל לקום כל כך מוקדם ביום שלישי can be understood from context
• אני לא רגיל לקום כל כך מוקדם בימי שלישי makes the recurring meaning clearer

Yes, it is completely natural.

The sentence is structured like this:

• אני = subject
• לא = negation
• רגיל = predicate adjective
• לקום = infinitive complement
• כל כך מוקדם = degree + time expression
• ביום שלישי = time phrase

So the full flow is:

I + not + used + to get up + so early + on Tuesday

That is a very normal Hebrew sentence pattern.

Sometimes yes, especially in casual speech, if the subject is already clear from context.

For example, in conversation someone might say:

• לא רגיל לקום כל כך מוקדם ביום שלישי

But in a full standalone sentence, especially for learners, keeping אני is best and most natural:

• אני לא רגיל לקום כל כך מוקדם ביום שלישי

So omitting it is possible, but not necessary.

A woman would say:

אני לא רגילה לקום כל כך מוקדם ביום שלישי.

The only change is:

• רגיל → רגילה

That is because the adjective must match the speaker’s gender. Everything else stays the same.