Se chover, leva o impermeável.

Because Portuguese normally uses the future subjunctive after se when talking about a possible future condition.

So:

• Se chover = If it rains
• not Se chove for this meaning

This is different from English, where we use a present form after if:

• If it rains, take the raincoat.

In Portuguese, the idea is future possibility, so chover is the correct form here.

Yes. In this sentence, chover is the future subjunctive form, even though it looks identical to the infinitive.

That happens with many verbs in some forms. So here:

• infinitive: chover
• future subjunctive (for ele/ela/você, and also often with no explicit subject): chover

A good way to see the difference is with irregular verbs:

• se for = if he/she/you go(es)
• se tiver = if he/she/you have(s)

So even though chover looks unchanged, its job in the sentence is grammatical, not infinitive.

Here, leva is the affirmative imperative of tu:

• levar = to take
• leva! = take!

So the sentence is giving an instruction to one person in an informal tu form:

• Se chover, leva o impermeável.
• If it rains, take the raincoat.

This is very common in European Portuguese.

Because leva is the command form for tu, while leve is the command form for você / o senhor / a senhora.

So:

• tu → leva
• você → leve

Examples:

• Se chover, leva o impermeável. → informal, speaking to tu
• Se chover, leve o impermeável. → more formal

In Portugal, tu is very common in everyday speech, so leva sounds natural.

Portuguese often leaves subject pronouns out when they are already clear from the verb form.

So instead of saying:

• Se chover, tu leva o impermeável.

Portuguese normally says:

• Se chover, leva o impermeável.

The verb leva already tells you the instruction is directed to tu.

This omission is very normal in Portuguese and much more common than in English.

Because Portuguese often uses the definite article where English might use a, the, or even your, depending on context.

So o impermeável can mean something like:

• the raincoat
• your raincoat
• the raincoat you would normally take

It refers to a specific, understood item.

If you said um impermeável, that would sound more like:

• a raincoat, any raincoat, not a specific one

So both are possible in some contexts, but o impermeável suggests a more definite, expected item.

No. Impermeável can be:

1. an adjective meaning waterproof
2. a noun meaning raincoat

Examples:

• um casaco impermeável = a waterproof coat
• o impermeável = the raincoat

In your sentence, it is being used as a noun.

Not for this usual future meaning.

For a future condition, Portuguese prefers:

• Se chover, leva o impermeável.

Se chove would not be the normal choice here. A learner should strongly prefer se + future subjunctive for this kind of sentence.

If you wanted a different nuance, for example if it is raining, you might hear:

• Se estiver a chover, leva o impermeável.

That means something more like If it happens to be raining / If it is raining at the time.

So:

• Se chover = if it rains
• Se estiver a chover = if it is raining

Because the conditional clause comes first.

In Portuguese, when a clause like Se chover comes before the main clause, it is normally separated by a comma:

• Se chover, leva o impermeável.

If you reverse the order, you usually do not use a comma:

• Leva o impermeável se chover.

So the comma here is standard punctuation.

Yes. That is perfectly natural.

Both mean the same thing:

• Se chover, leva o impermeável.
• Leva o impermeável se chover.

The first version puts the condition first, which can feel slightly more like In case it rains... The second starts with the instruction.

In the second version, you would normally write it without a comma.

It works in both European and Brazilian Portuguese, but it feels especially natural for European Portuguese because of the use of tu with leva.

In European Portuguese, tu is widely used in everyday conversation, so:

• Se chover, leva o impermeável.

is very normal.

A more formal version would be:

• Se chover, leve o impermeável.

So the grammar is not exclusive to Portugal, but the choice of leva fits European Portuguese very well.