Kesäloma alkaa kesäkuun lopussa, ja heinäkuussa olen yleensä täysin vapaa.

In Finnish, compound nouns are usually written as one word.
So kesäloma = kesä (summer) + loma (holiday / vacation).

This is very common in Finnish:

• kesäloma = summer holiday
• talviloma = winter holiday
• koulukirja = school book
• jalkapallo = football

English often writes these as two words, but Finnish usually joins them.

Alkaa means to begin or to start.

In this sentence, Kesäloma alkaa means The summer holiday begins.

A useful point: alkaa is normally intransitive, so it does not take a direct object in the same way English sometimes does. You say:

• Loma alkaa = The holiday begins
• Elokuva alkaa = The film starts

The thing that starts is the subject.

Because Finnish uses a structure equivalent to at the end of June:

• kesäkuun = of June
• lopussa = at/in the end

So:

• kesäkuun lopussa = at the end of June

Here, kesäkuu becomes kesäkuun, which is the genitive form. The genitive is often used when one noun defines another:

• vuoden alussa = at the beginning of the year
• kuun lopussa = at the end of the month
• kesäkuun lopussa = at the end of June

Lopussa is in the inessive case, which usually has the ending -ssa / -ssä and often means in.

The base form is loppu = end.
So:

• loppu = end
• lopussa = in the end / at the end

In time expressions, Finnish often uses the inessive where English uses prepositions like in or at:

• vuoden alussa = at the beginning of the year
• päivän lopussa = at the end of the day

So kesäkuun lopussa is literally something like in June’s end, but naturally it means at the end of June.

Because Finnish often uses the inessive case for months when meaning in a month.

• heinäkuu = July
• heinäkuussa = in July

Other examples:

• tammikuussa = in January
• maaliskuussa = in March
• joulukuussa = in December

So heinäkuussa olen yleensä täysin vapaa means In July I am usually completely free.

Both come from month names ending in -kuu.

• kesäkuu = June
• kesäkuun = of June
• heinäkuu = July
• heinäkuussa = in July

So the endings are:

• -n for the genitive: kesäkuun
• -ssa for the inessive: heinäkuussa

This pattern is very common with Finnish month names.

Finnish often leaves out personal pronouns when the verb ending already shows who the subject is.

• olen already means I am
• so minä olen and olen both mean I am

In this sentence:

• olen yleensä täysin vapaa = I am usually completely free

Adding minä is possible, but it is often unnecessary unless you want emphasis:

• Minä olen yleensä täysin vapaa = I am usually completely free (with extra emphasis on I)

Finnish word order is flexible, and the first element often gives the topic or focus.

So:

• Heinäkuussa olen yleensä täysin vapaa puts emphasis on the time: In July, I am usually completely free.

You could also say:

• Olen heinäkuussa yleensä täysin vapaa

That is also understandable, but the original sounds very natural because it introduces the time first.

Yleensä means usually or generally.

In this sentence:

• olen yleensä täysin vapaa = I am usually completely free

It often appears near the verb, but Finnish adverbs can move around somewhat depending on emphasis:

• Olen yleensä vapaa
• Yleensä olen vapaa

Both are possible, but the nuance may shift slightly depending on what you want to highlight.

• täysin = completely, totally
• vapaa = free

So täysin vapaa means completely free.

Here vapaa means free in the sense of not busy, off work, or available.
It does not mean politically free or free of charge here.

Examples:

• Olen vapaa huomenna. = I’m free tomorrow.
• Hän on täysin vapaa ensi viikolla. = He/She is completely free next week.

Because vapaa is a predicate adjective after the verb olla (to be), and in this kind of basic sentence it is normally in the nominative singular.

So:

• olen vapaa = I am free
• hän on iloinen = he/she is happy
• me olemme valmiit = we are ready

If the subject changes, the adjective may also change in number:

• olen vapaa = I am free
• olemme vapaita = we are free

In your sentence, the understood subject is I, so singular vapaa is correct.

Finnish does not have articles like English a/an and the.

So Finnish simply says:

• Kesäloma alkaa
  literally summer holiday begins

Whether English uses the summer holiday, my summer holiday, or just summer vacation depends on context and translation, not on an article in Finnish.

This is a big difference from English, and learners often have to get used to understanding definiteness from context.

Yes, in a sentence like this, ja simply means and.

It connects the two clauses:

• Kesäloma alkaa kesäkuun lopussa
• ja heinäkuussa olen yleensä täysin vapaa

So it joins:

1. when the summer holiday begins, and
2. what the speaker’s situation is in July.

Yes. Finnish often uses the present tense to talk about the future when the time is clear from context.

So:

• Kesäloma alkaa kesäkuun lopussa
  literally uses present tense: The summer holiday begins at the end of June

But in meaning, it can refer to a future scheduled event, just like English sometimes does:

• School starts in August
• My holiday begins at the end of June

This is completely normal in Finnish.

Yes. The Finnish word loma covers both holiday and vacation, depending on the variety of English and the context.

So kesäloma can be translated as:

• summer holiday
• summer vacation

Both are correct.