Mense Februario pueri domi manere malunt, quia ventus frigidus est.

This is a very common Latin pattern: the ablative of time when.

• mense = in the month
• Februario = February, agreeing with mense

So Mense Februario literally means in the month of February.

Latin often uses the ablative case for time expressions without needing a preposition like in. English usually needs in, but Latin often does not.

You may also see simpler time expressions such as:

• aestate = in summer
• tertia hora = at the third hour
• eo die = on that day

So the lack of in is normal.

Because it has to match mense in case.

The base form is Februarius, but here it is describing mense, so it changes form:

• mensis Februarius = the month of February
• mense Februario = in the month of February

Both words are:

• ablative
• singular
• masculine

This matching is called agreement.

Here pueri is nominative plural, meaning the boys.

You can tell from the verb:

• malunt = they prefer

Since the verb is plural, pueri must be the plural subject: the boys.

It is true that pueri can also be genitive singular in some contexts, meaning of the boy, but not here. The sentence structure makes it clear that it is the subject.

domi means at home and is a special form called the locative.

Latin has a small set of words that can use the locative to express place where, especially:

• domi = at home
• ruri = in the countryside
• names of towns/cities sometimes do this too

So:

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

By contrast, in domo would mean more literally in the house, focusing on the building itself rather than the idea of being at home.

Because it depends on malunt.

malunt means they prefer, and after verbs like prefer, want, are able, Latin often uses an infinitive to express the action preferred, wanted, or able to be done.

So:

• manere = to remain / to stay
• malunt manere = they prefer to stay

This is very similar to English.

malunt is the 3rd person plural present active indicative of malo, which means to prefer.

Its principal parts are:

• malo
• malle
• malui

It is an irregular verb.

A useful way to understand it is historically:

• magis = more
• volo = I want

So malo originally meant something like I want more, which developed into I prefer.

Here:

• malunt = they prefer

So pueri ... malunt = the boys prefer ...

Yes, a different word order would be possible.

Latin word order is more flexible than English because grammatical endings do much of the work. The order here is natural and meaningful:

• Mense Februario sets the time first
• pueri gives the subject
• domi manere gives the idea of what they prefer
• malunt comes at the end of the main clause, which is very common in Latin
• quia ventus frigidus est gives the reason

Latin often places the verb near the end, especially in straightforward prose.

You could rearrange parts and still keep the same basic meaning, but the original order is smooth and idiomatic.

Because ventus is the subject, so it is nominative singular, and frigidus must agree with it.

• ventus = wind or the wind
• frigidus = cold
• est = is

So:

• ventus frigidus est = the wind is cold

Here frigidus is a predicate adjective. It still matches the subject in:

• gender: masculine
• number: singular
• case: nominative

That is why it is frigidus, not frigidum.

quia means because. It introduces a clause giving the reason.

So the sentence has:

• a main clause: Mense Februario pueri domi manere malunt
• a subordinate clause of reason: quia ventus frigidus est

Latin commonly uses quia this way, just as English uses because.

Because this sentence presents the reason as a straightforward fact.

• quia ventus frigidus est = because the wind is cold

Latin often uses the indicative after quia when the reason is stated simply and directly.

In some more advanced contexts, especially where the reason is presented as someone’s claim or viewpoint rather than an objective fact, Latin may use the subjunctive. But here the ordinary indicative est is exactly what you would expect.

Either can work, depending on context.

The basic meaning of maneo, manere is remain, stay, or continue to be in a place.

Here, with domi, English usually sounds most natural with stay:

• domi manere = to stay at home

But remain at home would also be accurate. Latin often has a broader range than any single English word, so both are good ways to understand it.