Τον Απρίλιο και τον Μάιο ο καιρός αλλάζει γρήγορα, οπότε έχω μαζί μου και ζακέτα και μακρυμάνικη μπλούζα.

In Greek, names of months often appear in the accusative with the article to mean in / during that month.

So:

• τον Απρίλιο = in April
• τον Μάιο = in May

This is a very common time expression pattern, similar to:

• τη Δευτέρα = on Monday
• τον χειμώνα = in winter

So Τον Απρίλιο και τον Μάιο is not a direct object here; it is a time expression.

Greek usually prefers to repeat the article with each item in a pair like this:

• τον Απρίλιο και τον Μάιο

That sounds more natural and complete than leaving the second article out. Repeating the article is very common when linking nouns with και, especially in set expressions and with time words.

Greek uses the definite article much more often than English.

So where English says weather, Greek normally says ο καιρός. This is the normal way to talk about weather as a general subject.

Compare:

• Ο καιρός αλλάζει. = The weather changes.

In English, dropping the would sound strange, and in Greek dropping ο here would also sound unnatural.

Αλλάζει is the 3rd person singular present of αλλάζω = to change.

It matches the subject ο καιρός:

• ο καιρός αλλάζει = the weather changes / is changing

Here the present tense expresses a general or repeated situation, not just something happening at this exact moment.

Here, γρήγορα is an adverb, meaning quickly.

It modifies the verb:

• αλλάζει γρήγορα = changes quickly

The related adjective is:

• γρήγορος = fast / quick (masculine)
• γρήγορη = fast / quick (feminine)
• γρήγορο = fast / quick (neuter)

So in this sentence, γρήγορα tells us how the weather changes.

Here, οπότε means so, therefore, or as a result.

It links the first idea to its consequence:

• The weather changes quickly, so I have ...

A useful thing to know is that οπότε can also mean when in other contexts, but in this sentence it clearly means so / therefore.

Έχω μαζί μου is a very common Greek expression meaning I have with me or I carry with me.

Literally:

• έχω = I have
• μαζί μου = with me

So:

• έχω μαζί μου ζακέτα = I have a cardigan with me

It is an idiomatic, natural way to say that you are carrying something or keeping it with you.

With short pronouns, μαζί normally combines with the genitive clitic forms:

• μαζί μου = with me
• μαζί σου = with you
• μαζί του / της = with him / her
• μαζί μας = with us

If you use a full stressed pronoun, you usually say:

• μαζί με μένα
• μαζί με σένα

So μαζί μου is the normal short form.

This is the Greek pattern και ... και ..., which means both ... and ....

So:

• και ζακέτα και μακρυμάνικη μπλούζα = both a cardigan and a long-sleeved top

The repetition adds emphasis and makes it clear that both items are included.

Without repetition, ζακέτα και μακρυμάνικη μπλούζα would still be grammatical, but και ... και ... is more explicit.

Greek often leaves out the indefinite article where English would use a / an, especially after a verb like έχω.

So Greek can naturally say:

• έχω ζακέτα
• έχω μπλούζα

You could also say:

• έχω μια ζακέτα και μια μακρυμάνικη μπλούζα

but leaving out μια is very normal and natural here.

Because it is an adjective agreeing with μπλούζα.

• μπλούζα is feminine singular
• so the adjective must also be feminine singular

That is why we get:

• μακρυμάνικη μπλούζα

Greek adjectives change form to match the noun’s gender, number, and case.

Greek word order is more flexible than English, and it is very common to put a time expression first to set the scene.

So the sentence starts by telling you when this happens:

• Τον Απρίλιο και τον Μάιο = In April and May

This is natural and similar to English sentences like:

• In April and May, the weather changes quickly...

It gives the time frame before the main statement.