Learn Hardcore Portuguese (Brazil): Nós costumamos caminhar no parque quando o tempo está bom. - We usually walk in the park when the weather is good.

Nós costumamos caminhar = “We usually walk” / “We’re in the habit of walking.”
Structure: costumar + infinitive
- Eu costumo ler. = I usually read.
- Eles costumam viajar. = They usually travel.

So costumamos isn’t just “we do,” it adds the idea of habit or regularity.

Why say nós costumamos caminhar instead of just caminhamos?

Both are possible, but they’re not identical in nuance:

Nós caminhamos no parque = “We walk in the park” (simple present; can be habitual or a description of something that happens in general).
Nós costumamos caminhar no parque = “We usually walk in the park” (explicitly says it’s a habit or routine).

Using costumar makes the idea of “usually / as a rule” very clear, which matches the English “We usually walk in the park when the weather is good.”

Is nós required, or can I just say Costumamos caminhar no parque...?

You can drop nós:

Costumamos caminhar no parque quando o tempo está bom.

In Portuguese, the verb ending -amos already shows the subject is nós (we), so the subject pronoun is often omitted. Including nós is fine and very common; omitting it is also completely correct and often sounds more natural in context.

So both are correct:

Nós costumamos caminhar...
Costumamos caminhar...

How is costumar conjugated in the present tense?

Costumar is a regular -ar verb. Present tense:

eu costumo – I usually …
você / ele / ela costuma – you (sg.) / he / she usually …
nós costumamos – we usually …
vocês / eles / elas costumam – you (pl.) / they usually …

Example:

Eles costumam caminhar no parque. = They usually walk in the park.

What does no in no parque mean?

No is a contraction of the preposition em (in, on, at) + the masculine singular article o (the):

em + o = no

So:

no parque = “in the park” / “at the park” (literally “in the + park”)

Similarly:

na escola = em + a (in the school)
nos parques = em + os (in the parks)
nas casas = em + as (in the houses)

Why do we use an article in no parque instead of just em parque?

Portuguese normally uses the definite article with singular countable nouns in cases where English might omit the.

So:

no parque = “in the park” (general, not necessarily one specific known park)
em parque sounds strange and is usually incorrect in this context.

Talking about “in parks” in general would be:

em parques (no article, plural and more generic).

What’s the difference between caminhar and andar?

Both can involve walking, but they’re used a bit differently:

caminhar: to walk (often with a sense of going for a walk, exercising, or walking some distance)
- Gosto de caminhar de manhã. = I like to go for a walk in the morning.
andar: to walk, to go around, to move, to ride (depending on context)
- Ele ainda não anda. = He doesn’t walk yet (a baby).
- Eu ando de bicicleta. = I ride a bicycle.
- Andei pelo centro. = I walked around downtown.

In your sentence, caminhar no parque suggests something like “go for a walk in the park,” which matches the idea of a regular, maybe health-related activity.

Could I say andar no parque instead of caminhar no parque?

Yes, andar no parque is possible, but it’s a bit broader and more context-dependent:

caminhar no parque: very clearly “to go for a walk in the park,” usually as exercise or leisure.
andar no parque: could be “to walk around in the park,” but might also just mean “to be around / moving in the park.”

In many everyday contexts, people do say andar no parque and it will be understood as walking, but caminhar no parque is more precise for “go for walks in the park.”

What does tempo mean in quando o tempo está bom?

Tempo can mean either:

time
weather

In this sentence, tempo clearly means weather:

quando o tempo está bom = “when the weather is good”

Examples:

Não tenho tempo. = I don’t have time.
O tempo está horrível hoje. = The weather is horrible today.

Why is it está bom and not é bom in o tempo está bom?

Estar is used for states or conditions that are seen as temporary or changeable:

O tempo está bom. = The weather is good (right now / these days).

Ser is used for more permanent or characteristic qualities:

O clima aqui é bom. = The climate here is good (generally, as a characteristic of the place).

Weather is something that changes, so estar is the natural choice for “the weather is good (now).”

Are there other common ways to say “when the weather is good”?

Yes. Some common alternatives:

Quando faz bom tempo. – Literally “when it makes good weather,” very idiomatic.
Quando o tempo está agradável. – “when the weather is pleasant.”
Quando o tempo está bonito. – “when the weather is nice.”
Quando não está chovendo. – “when it’s not raining.”
Quando faz sol. – “when it’s sunny.”

Your sentence:

quando o tempo está bom is perfectly natural and widely used.

Can I change the word order to put quando o tempo está bom at the beginning?

Yes. Both orders are natural:

Nós costumamos caminhar no parque quando o tempo está bom.
Quando o tempo está bom, nós costumamos caminhar no parque.

Putting the quando clause first is very common and sounds completely normal, just like in English: “When the weather is good, we usually walk in the park.”

How would I turn this into a question like “Do you usually walk in the park when the weather is good?” in Portuguese?

For vocês (you plural):

Vocês costumam caminhar no parque quando o tempo está bom?

Notes:

The structure stays the same; Portuguese doesn’t need an auxiliary “do.”
The only change is moving to vocês costumam (you [pl.] usually) instead of nós costumamos (we usually).
Intonation and the question mark signal that it’s a question.

How do you pronounce costumamos and where is the stress?

Costumamos is pronounced roughly like:

kos-too-MA-mos (Brazilian Portuguese)

Details:

Stress falls on -ma-: cos-tu-MA-mos.
The c is a hard k sound.
The o in the first syllable is like the o in “cot” (depending on accent).
The second u is like “oo” in “food,” but shorter.

So: cos-tu-MA-mos.