Learn Spanish (Latin America): Siempre viajamos en junio y julio.

In Spanish, months of the year are always written with lowercase letters unless they are the very first word of a sentence. This rule also applies to days of the week and seasons.

Do we always use en to say that something happens in a specific month?

Yes! Just like in English, you use the preposition en right before the month to say an event happens during that time, as in en junio.

Where is the word for 'we' in this sentence?

It is built right into the verb. The -amos ending on viajamos tells us the subject is nosotros (we). You could say Nosotros siempre viajamos, but Spanish speakers usually drop the pronoun because the verb ending makes it perfectly clear.

Does siempre have to go before the verb?

Usually, yes. Just like in English where we say 'We always travel' instead of 'We travel always', Spanish generally places siempre right before the main verb.