How do say have a wonderful summer in french?

There are a few ways to say "have a wonderful summer" in French, depending on the level of formality and the specific nuance you want to convey:

Formal:

* Passez un excellent été! (This is the most direct and formal translation.)

* Je vous souhaite un été agréable. (This expresses a wish for a pleasant summer.)

Informal:

* Bon été! (This is a very common and casual way to say "have a nice summer.")

* Profitez bien de l'été! (This means "enjoy the summer!" and implies a desire for them to have fun.)

* Passe un super été! (This is a more informal way to say "have a great summer!")

You can also add a specific wish to your message, such as:

* Profitez du soleil! (Enjoy the sun!)

* Faites de belles vacances! (Have a great vacation!)

* Amusez-vous bien! (Have fun!)

The best option will depend on your relationship with the person and the specific situation.