En mai, quand il fait beau, nous déjeunons sur la terrasse presque tous les dimanches.

French uses en with most months: en mai, en juin, en décembre, etc.

So:

• en mai = in May

You do not normally use an article with months in this kind of expression.

Examples:

• en avril
• en août
• en janvier

So En mai is the standard way to say In May.

In French, months usually appear without an article when you are simply naming the month.

So you say:

• en mai
• mai est un joli mois

not:

• en le mai

You may see an article in other structures, but in a basic time expression like this, mai stands alone.

Here, quand means when.

So:

• quand il fait beau = when the weather is nice / when it’s nice out

Yes, lorsque could also work here:

• lorsqu’il fait beau

But quand is more common and natural in everyday speech. Lorsque can sound a bit more formal or literary.

Il fait beau is a fixed French weather expression.

Literally, it uses an impersonal il, but in normal English it means:

• the weather is nice
• it’s nice out

French often uses faire for weather:

• il fait beau = it’s nice out
• il fait mauvais = the weather is bad
• il fait chaud = it’s hot
• il fait froid = it’s cold

C’est beau usually means it is beautiful, talking about a thing, place, or sight, not the weather in general.

Because the subject is the impersonal pronoun il, which is singular.

In il fait beau, French treats the whole expression as a set phrase. You do not change fait to match some hidden plural idea. It always stays singular:

• il fait beau
• il fait froid
• il fait mauvais

The present tense is used here to describe a habit or something that happens regularly.

So:

• nous déjeunons sur la terrasse presque tous les dimanches

means something like:

• we have lunch on the terrace almost every Sunday

This is not just about what is happening right now. It is a habitual present.

French often uses the simple present for routines:

• Je travaille le lundi.
• Nous sortons souvent le soir.

In modern standard French, déjeuner usually means to have lunch.

So:

• nous déjeunons = we have lunch

Be careful, because in some regions or older usage, meal words can vary. For example:

• in standard French: petit-déjeuner = breakfast, déjeuner = lunch, dîner = dinner
• in some regional varieties, especially historically, déjeuner can refer to breakfast

But for most learners of standard French, here it clearly means have lunch.

Sur la terrasse is the normal choice because a terrace is seen as a surface or outdoor area that you are on.

So:

• sur la terrasse = on the terrace

Compare:

• dans la maison = in the house
• sur la terrasse = on the terrace

You may hear en terrasse in some contexts, especially when talking about sitting outside at a café:

• prendre un café en terrasse

But in this sentence, sur la terrasse is very natural.

Because presque modifies the whole idea tous les dimanches.

• tous les dimanches = every Sunday
• presque tous les dimanches = almost every Sunday

So presque comes directly before the expression it modifies.

This is the same pattern as:

• presque toujours = almost always
• presque tous les jours = almost every day
• presque personne = almost nobody

Both can mean every Sunday.

• tous les dimanches
• chaque dimanche

In many contexts, they are very close in meaning. In this sentence, either could work.

A small nuance:

• chaque dimanche can feel a little more focused on each individual Sunday
• tous les dimanches often feels more like a general repeated habit

But in everyday use, the difference is often minimal.

Because dimanches is plural, so French uses the plural form tous.

• tout = singular masculine
• tous = plural masculine
• toute = singular feminine
• toutes = plural feminine

Since dimanche is masculine, plural is:

• tous les dimanches

Compare:

• tout le jour = the whole day
• tous les jours = every day

The commas separate introductory and inserted time expressions:

• En mai,
• quand il fait beau,
• main clause: nous déjeunons sur la terrasse presque tous les dimanches.

This punctuation helps the sentence read clearly in French, just as in English when you have an opening phrase like:

• In May, when the weather is nice, we have lunch...

The commas are especially natural because quand il fait beau is inserted before the main clause.

Yes. French allows some flexibility, especially with time expressions.

For example, you could also say:

• Nous déjeunons sur la terrasse presque tous les dimanches en mai, quand il fait beau.
• Quand il fait beau, en mai, nous déjeunons sur la terrasse presque tous les dimanches.

But the original order is very natural because it sets the scene first:

1. En mai
2. quand il fait beau
3. main action

That makes it easy to understand the context before the main statement.

In a normal statement, yes, nous is necessary.

French subject pronouns are usually required:

• nous déjeunons
• ils arrivent
• elle parle

You cannot normally drop nous the way Spanish or Italian often drop subject pronouns.

Also, déjeunons by itself could sound like an imperative:

• Déjeunons ! = Let’s have lunch!

So in this sentence, nous déjeunons clearly means we have lunch.

A rough pronunciation is:

• nous ≈ noo
• déjeunons ≈ day-zhuh-non

A few useful points:

• the j sound in déjeunons is like the s in measure
• the final -s of nous is normally silent
• there is often a liaison before a vowel sound, so nous déjeunons can sound smoothly connected

You do not pronounce every written letter separately. French pronunciation is more fluid than the spelling may suggest.