Vespere omnes domum revertuntur, quia ventus frigidus est.

Because Latin often expresses time when with the ablative case and no preposition.

So vespere means in the evening or toward evening. English usually needs in, but Latin often does not.

You can think of it as an adverbial ablative:

• vespere = in the evening
• compare similar time expressions like nocte = at night

So the lack of a preposition is normal Latin usage.

It is ablative singular.

Here it is being used adverbially to tell when the action happens. That is why it does not act like the subject or object of the sentence.

Omnes is the nominative plural of omnis, and here it means all (people) or everyone.

It is being used substantively, which means the noun is understood rather than stated. So literally it is something like:

• omnes = all [people]

Depending on the context, English might translate it as:

• everyone
• all of them
• they all

Because Latin is thinking in terms of all people, which is naturally plural.

So even though English may say everyone returns, Latin uses a plural word and a plural verb:

• omnes = plural
• revertuntur = plural

A very literal translation would be all return home.

Domum is a special accusative form meaning homeward / to home / home after verbs of motion.

Latin has a special construction for motion toward home:

• domum = home
• no ad is needed

So:

• domum revertuntur = they return home

This is similar to the way Latin also uses the accusative without a preposition for motion toward towns and small islands.

A useful set to remember is:

• domum = to home / home
• domi = at home
• domo = from home

Revertuntur is third person plural, present indicative.

It agrees with omnes, so it means:

• they return
• they are returning

The tense is present, and the plural ending shows that the subject is plural.

Because revertor is a deponent verb.

Deponent verbs:

• have passive forms
• but active meanings

So although revertuntur looks like they are being returned, it actually means they return.

This is a very common thing in Latin, and learners usually just have to get used to recognizing deponent verbs.

Quia means because and introduces a clause giving the reason.

So:

• quia ventus frigidus est = because the wind is cold

It is a very common way to introduce a cause or explanation.

Because this is a straightforward statement of fact.

Latin commonly uses the indicative after quia when the reason is presented as real or factual:

• ventus frigidus est = the wind is cold

So the sentence is simply stating the reason, not presenting it as doubtful, reported indirectly, or hypothetical.

Because Latin word order is much freer than English word order.

Both of these are possible in Latin:

• frigidus ventus
• ventus frigidus

In this sentence, frigidus comes after ventus, but it still clearly agrees with it:

• ventus = nominative singular masculine
• frigidus = nominative singular masculine

So the meaning is still the cold wind or, with est, the wind is cold.

Because Latin often places the verb later in the sentence, especially the verb to be.

So:

• ventus frigidus est

is a very natural Latin order.

English usually prefers the wind is cold, with the verb in the middle, but Latin often saves the verb for the end.

The present tense in Latin can do both, depending on context.

So this sentence could mean:

• a general habit: In the evening everyone returns home, because the wind is cold
• or a present-time description: Everyone is returning home in the evening, because the wind is cold

Without more context, many learners would naturally take it as a general or habitual statement.

Yes.

That is a perfectly natural way to bring out the plural force of omnes and revertuntur.

Possible English translations include:

• everyone returns home
• they all return home
• all go back home

The exact English wording depends on style, not on a major difference in the Latin.