Em julho e agosto, a cidade muda muito, mas em novembro e dezembro tudo fica mais calmo.

Here em means in when talking about months.

• em julho = in July
• em agosto = in August
• em novembro e dezembro = in November and December

Portuguese often uses em for time expressions like months, seasons, and longer periods:

• em janeiro
• em 2025
• em Portugal
• no verão (in the summer, where no = em + o)

So in this sentence, em introduces the time period when these changes happen.

In Portuguese, the names of months are normally written with lowercase letters, unlike in English.

So:

• julho
• agosto
• novembro
• dezembro

This is standard in both European and Brazilian Portuguese.

Portuguese normally uses month names without an article in this kind of expression.

So you say:

• em julho
• em agosto
• em novembro

Not:

• em o julho

With months, the article is usually not needed unless you are using a more specific structure in a different context. In this sentence, the simple and natural form is just em + month.

Because Portuguese, like English, links the two months with e = and:

• julho e agosto
• novembro e dezembro

You do not need to repeat em before both months if they belong to the same time phrase. So:

• em julho e agosto = in July and August

This is more natural than repeating:

• em julho e em agosto

That repeated version is possible for emphasis, but it is less neutral here.

Both are in the present indicative:

• muda = from mudar
• fica = from ficar

They are 3rd person singular, because the subjects are singular:

• a cidade → muda
• tudo → fica

In this sentence, the present tense is used for a general or habitual fact, not necessarily something happening right now at this exact moment. It means this is what typically happens during those months.

Because the sentence is describing a general pattern or recurring situation, not an action in progress at one specific moment.

• a cidade muda muito = the city changes a lot / the city is very different
• a cidade está a mudar would mean the city is changing right now, in progress

So the simple present is the natural choice here.

Muda comes from mudar, meaning to change.

In this sentence, a cidade muda muito means the city becomes very different in some way during July and August. It does not necessarily mean one single dramatic transformation; it often suggests that the atmosphere, population, rhythm, or daily life changes a lot.

So mudar here is broad and flexible: to change, to become different, to be different from usual.

Muito here means a lot.

• a cidade muda muito = the city changes a lot

Placed after the verb, it works like an adverb modifying muda.

Compare:

• muda muito = changes a lot
• é muito calma = is very calm

So muito can mean either a lot or very, depending on how it is used.

In this sentence, because it follows the verb muda, it means a lot.

The comma separates the first part of the sentence from the second:

• Em julho e agosto, a cidade muda muito
• mas em novembro e dezembro tudo fica mais calmo

The opening time phrase Em julho e agosto is placed before the main clause, so a comma helps mark that introductory element. Then mas introduces a contrast.

It is similar to English:

• In July and August, the city changes a lot, but in November and December everything becomes calmer.

Mas means but.

It introduces a contrast between two situations:

• in July and August, the city changes a lot
• in November and December, everything becomes calmer

So mas shows that the second part is different from, or opposite to, the first.

Tudo means everything.

Instead of saying again a cidade, the sentence broadens the idea:

• a cidade muda muito = the city changes a lot
• tudo fica mais calmo = everything becomes calmer

This suggests that not only the city in general, but the overall environment, daily life, streets, atmosphere, and activity all become calmer.

It is a natural stylistic choice and makes the sentence sound less repetitive.

Because calmo agrees with tudo.

Tudo is grammatically treated as masculine singular, so the adjective must also be masculine singular:

• tudo fica mais calmo

If the subject were feminine singular, you would use calma:

• a cidade fica mais calma

So the difference is caused by agreement with the subject:

• a cidade → feminine singular → calma
• tudo → masculine singular → calmo

Here ficar means to become rather than to stay.

So:

• tudo fica mais calmo = everything becomes calmer

This is a very common use of ficar in Portuguese. It often expresses a change of state:

• ficar triste = to become sad
• ficar cansado = to become tired
• ficar melhor = to get better

So in this sentence, ficar mais calmo means that things become quieter or less busy.

Mais calmo means calmer or more calm.

The sentence is comparing November and December with the busier period mentioned before. It implies that things are calmer than in July and August.

Portuguese usually forms the comparative with:

• mais + adjective

Examples:

• mais calmo = calmer
• mais barato = cheaper
• mais interessante = more interesting

So mais calmo expresses comparison.

It is singular because it agrees grammatically with tudo.

In Portuguese, adjectives usually agree with the noun or pronoun they describe in gender and number.

Since tudo is treated as masculine singular, the adjective must be:

• calmo

Not:

• calma
• calmos
• calmas

So this is mainly a grammar agreement issue, not just a vague general meaning.

Yes, that would also be correct, but it would mean something slightly different in focus.

• tudo fica mais calmo = everything becomes calmer
• a cidade fica mais calma = the city becomes calmer

The original sentence uses tudo to give a broader sense: the whole atmosphere, surroundings, and activity level settle down. Using a cidade again would be more repetitive and slightly narrower in effect.

Because Portuguese often uses the present tense to describe regular, repeated, seasonal facts.

So this sentence means something like:

• In July and August, the city tends to change a lot, but in November and December everything tends to be calmer.

It is not talking about one single future year only. It describes a typical pattern.

If you wanted to refer specifically to the future, you could use future forms, but that would change the tone and meaning.

It can naturally mean during that period, covering both months together, and it also implies that this is true in each of those months.

In other words, the sentence does not force a strong distinction between:

• November and December as a two-month period
• November individually and December individually

Portuguese often leaves that broad and natural.

Yes. The sentence is fully natural in European Portuguese.

Nothing in it is strange or overly formal. It sounds like normal written or spoken Portuguese. Also, the structure with ficar mais calmo and the use of simple present for recurring situations are very natural in European Portuguese.