Using "en" for time

Question

When do you use "en" with the date or day and when do you omit it? And the definite article? Do you only omit it when you are talking about a day of the week, or a specific date overall?

Tell me which of these are wrong and which are right, please!

Vamos a salir en julio. (I know this one is right.)

Vamos a salir el viernes. (?en el viernes?)

Vamos a salir el tres de julio. (?en el tres de julio?)'

Is this okay as well?

Vamos a salir para el tres de julio.

Answer 1

Great question! You should not use "en" with days and dates. We use "en" as you noted, with months. For days and dates we use "el".

Vamos a salir el viernes. Vamos a salir el tres de julio.

Also, you can use "para" with a date, but your example sentence sounds awkward. A more likely use of "para" with a date would indicate a deadline:

La tarea es para el tres de julio. The homework is for July 3rd.

Can a translation of my use of "para" mean "We're going to leave by July 3"? Is it still awkward with that meaning? - Luciente, May 10, 2010