Why do spanish speakers use the present tense to refer to a future event?

Grammar Genius,

Is ¨le llamo mañana¨correct? Or, "nos estamos en contacto"? Why do I use the present tense to refer to the future?

Calling the Spanish present tense the ´present´ may be misleading because it also refers to the past, the future, as well as timeless statements.

It is grammatically correct to say:

"Te veo lluego" I will call you tomorrow.
"mañana vamos a Costa Rica" Tomorrow we are going to Costa Rica .

The present tense may be used to refer to the future. This is especially common in some Latin American countries.

When used with inanimate things, it usually refers to a set or arranged time. Compare:

"El bus sale a las 9." The bus leaves at nine. (That is the set schedule.)

"El bus saldrá a las 9." The bus will leave at nine. (It normally leaves at a different time)