Learn Hardcore French: Pendant la canicule, il vaut mieux boire beaucoup d’eau et rester à l’ombre. - During a heatwave, it is better to drink plenty of water and stay in the shade.

So il vaut mieux literally means “it is worth better,” but the natural English equivalent is “it’s better (to)…”. The il is just a grammatical subject required by French; it doesn’t carry any real meaning here.

Why do we say il vaut mieux boire… and not something like il vaut mieux on boit…?

After il vaut mieux, French normally uses either:

An infinitive (general advice)
- Il vaut mieux boire beaucoup d’eau.
  → It’s better to drink a lot of water. (in general)
Que + subjunctive (advice about a specific subject)
- Il vaut mieux que tu boives beaucoup d’eau.
  → It’s better if you drink a lot of water.

Using a conjugated verb directly after il vaut mieux (like il vaut mieux on boit) is ungrammatical. French needs either the infinitive or que + subjunctive there.

Can I say c’est mieux de boire beaucoup d’eau instead of il vaut mieux boire beaucoup d’eau?

You can say C’est mieux de boire beaucoup d’eau, and people will understand you, but:

Il vaut mieux + infinitive sounds more idiomatic and natural for giving advice.
C’est mieux de + infinitive is used, but many teachers consider it less elegant or a bit “learner‑like.”

More natural alternatives with c’est mieux would be:

C’est mieux si tu bois beaucoup d’eau.
C’est mieux de rester à l’ombre que de rester en plein soleil.

For a clean, standard recommendation, Il vaut mieux boire… is the best choice.

Why are boire and rester in the infinitive form here?

They’re infinitives because of the construction il vaut mieux + infinitive:

Il vaut mieux boire…
Il vaut mieux rester…

This structure expresses general advice: “It’s better to drink and to stay…,” without tying the action to a specific person (I/you/we).

If you want to talk about a specific subject, you switch to il vaut mieux que + subjunctive:

Il vaut mieux que tu boives beaucoup d’eau.
Il vaut mieux que nous restions à l’ombre.

Why is it pendant la canicule and not just en canicule or something else?

Pendant is the normal preposition for “during” a period of time:

Pendant l’été = during the summer
Pendant la nuit = during the night
Pendant la canicule = during the heatwave

En canicule is not idiomatic; French doesn’t usually use en with canicule like that.

You could also say, with slightly different nuance:

Lors d’une canicule = during a heatwave (more formal)
En cas de canicule = in case of a heatwave

But for a straightforward “during the heatwave,” pendant la canicule is the most natural.

Why is it la canicule and not une canicule, or just canicule with no article?

French uses the definite article (le / la / les) much more than English when speaking in general terms:

La chaleur est dangereuse.
= Heat is dangerous.
La canicule est dangereuse pour les personnes âgées.
= Heatwaves are dangerous for elderly people.

In your sentence, la canicule can be taken as:

“the heatwave” currently happening, or
“the heatwave period” as a type of situation (a generic idea).

You could say une canicule if you mean “a particular heatwave, one heatwave among others”, for example:

Pendant une canicule comme celle de 2003…
During a heatwave like the one in 2003…

But dropping the article (pendant canicule) is ungrammatical in French; common nouns almost always need an article.

Why is it beaucoup d’eau and not beaucoup de l’eau?

With quantities like beaucoup, French uses this pattern:

beaucoup de + noun (without article)

Examples:

beaucoup d’eau = a lot of water
beaucoup de gens = a lot of people
beaucoup de travail = a lot of work

So in your sentence, the correct form is beaucoup d’eau, not beaucoup de l’eau.

You would only see something like beaucoup de l’eau in a very specific context, where “the water” has already been defined:

Il a bu beaucoup de l’eau que tu avais préparée.
He drank a lot of the water that you had prepared.

That’s rare and quite marked. For general advice (“drink a lot of water”), you must say beaucoup d’eau.

Why d’eau and not de eau? What’s going on with the apostrophe?

The apostrophe is due to elision: French drops certain final vowels before a word starting with a vowel or silent h.

de + eau → d’eau
je + aime → j’aime
le + homme → l’homme

So beaucoup de eau would sound clumsy and is not allowed; it must be beaucoup d’eau.

A useful detail: eau is feminine ( une eau, l’eau). You see the same elision with l’ before it:

l’eau est froide (not la eau).

Why is it rester à l’ombre and not rester dans l’ombre?

Both exist, but they don’t mean quite the same thing.

Rester à l’ombre
= Stay in the shade (out of the sun, in a cool/shady spot).
This is the normal, idiomatic expression for protecting yourself from the sun.
Rester dans l’ombre
Literally: stay in the shadow / darkness.
Often has a more literal or figurative sense:
- physically in the dark, not in the light
- or figuratively “stay in the background, unknown, out of the spotlight”

So for advice about heat and sun, you almost always say rester à l’ombre.

Why is there a comma after Pendant la canicule? Do I have to put that phrase at the beginning?

Pendant la canicule is an introductory time phrase (“During the heatwave”), and putting a comma after such an introduction is standard written French:

Pendant la canicule, il vaut mieux…

You can move the phrase to the end:

Il vaut mieux boire beaucoup d’eau et rester à l’ombre pendant la canicule.

Both orders are grammatically correct. The difference is stylistic:

At the beginning, it sets the context first (When? During the heatwave), then the advice.
At the end, the focus starts on the advice, and the time frame feels like extra information added after.

In spoken French, intonation usually marks this pause; in writing, the comma makes it clear.