Quand il fait beau, nous prenons le café sur la terrasse et nous regardons les enfants courir dans l’allée.

Il fait beau is a fixed, very common weather expression meaning that the weather is nice or pleasant.

• il here is an impersonal subject. It does not mean a real he.
• fait comes from faire.
• French often uses faire in weather expressions:
  
  • il fait beau = the weather is nice
  • il fait chaud = it is hot
  • il fait froid = it is cold

So you should learn il fait beau as a whole expression.

Quand means when. It introduces a time clause: when the weather is nice.

In this sentence, it does not mean one specific moment only. With the present tense, it often gives a habitual idea:

• Quand il fait beau, nous prenons le café...
  = When the weather is nice, we have coffee...

So the sense is more like whenever the weather is nice.

French uses the present tense not only for what is happening right now, but also for habits and general routines.

Here, the sentence describes something people usually do:

• nous prenons
• nous regardons

So the present tense means something like:

• we usually have coffee
• we watch the children run

This is very natural in French, just as in English: When the weather is nice, we have coffee on the terrace...

Prendre le café is an idiomatic French expression. It often means to have coffee or to sit down for coffee, not just the physical act of drinking it.

There is a small difference in feel:

• boire du café = to drink coffee
• prendre le café = to have coffee, often as a social moment or part of a routine

So nous prenons le café sur la terrasse sounds very natural for we have coffee on the terrace.

In many everyday expressions, French uses the definite article where English might not.

So:

• prendre le café
• prendre le petit-déjeuner
• prendre le thé

These are set expressions.

If you said boire du café, then du would make sense because it means some coffee. But with prendre le café, French normally uses le.

Sur usually means on, but with places like la terrasse, English often translates it as on the terrace or out on the terrace.

French says:

• sur la terrasse
• sur le balcon

This is the normal preposition for being out on that kind of open surface or outdoor area.

French often repeats the subject pronoun when there are two full verbs joined by et:

• nous prenons le café sur la terrasse et nous regardons les enfants courir

This is clear and completely natural.

Could French omit the second nous? Yes, sometimes:

• Quand il fait beau, nous prenons le café sur la terrasse et regardons les enfants courir.

But repeating nous is usually clearer and more standard, especially for learners and in careful written French.

After verbs of perception like voir, entendre, écouter, and regarder, French often uses:

subject + perception verb + object + infinitive

So:

• nous regardons les enfants courir
• literally: we watch the children run

Here:

• les enfants is the object of regardons
• courir is an infinitive describing what we see them doing

French does not use a second conjugated verb here. So les enfants courent would not fit this structure.

Compare:

• Nous regardons les enfants courir. = We watch the children run.
• Les enfants courent. = The children are running.

It can match either English phrasing depending on context.

French often uses the infinitive after a perception verb where English may use either:

• watch the children run
• watch the children running

The French structure does not necessarily force a big difference between those two English versions. It simply means that you are watching them in the act of running.

Courir is the infinitive of the verb to run.

Its basic forms include:

• courir = to run
• je cours = I run / I am running
• nous courons = we run / we are running

In this sentence, it stays in the infinitive because it follows regardons les enfants in the perception-verb pattern.

French usually shortens la to l’ before a vowel sound. This is called elision.

So:

• la terrasse
• l’allée

Because allée begins with a vowel, la allée becomes l’allée.

Une allée can mean a path, driveway, lane, or walkway, depending on context.

In a sentence like this, it usually suggests a passage or path near the house or garden area, where the children are running.

It is a feminine noun:

• une allée
• l’allée

The comma separates the introductory time clause from the main clause:

• Quand il fait beau, = introductory clause
• nous prenons le café... = main clause

This is also common in English:

• When the weather is nice, we have coffee on the terrace...

The comma helps readability and is very natural here.

Yes. In everyday spoken French, many speakers would naturally use on instead of nous:

• Quand il fait beau, on prend le café sur la terrasse et on regarde les enfants courir dans l’allée.

This is very common in conversation.

The version with nous is more formal, more careful, and very standard in writing. So the sentence you have is perfectly correct and good to learn.

You could also use lorsque, but quand is more common and natural in everyday French.

• Quand il fait beau... = very common, neutral
• Lorsque il fait beau... is not correct as written, because lorsque becomes lorsqu’ before a vowel:
  • Lorsqu’il fait beau...

Lorsqu’il fait beau sounds a little more formal or literary than Quand il fait beau.