Va a llover, it's raining

Often when it rained in the rural area where I lived, someone would say "va a llover". It doesn't take much knowledge of Spanish to recognize this as a future tense. So, why would people say that it's going to rain right when it starts raining? It's anyone's guess, but here's mine:

This phrase is likely a projection of continued rain throughout the day. If it starts raining, and the outlook for the foreseeable hours in the day look grim, people will predict a considerable amount of rainfall, using only a three-word prhase.

I can respect this type of communication. People tend to shorten language when they're among people of similar background. Heck, why not use a few words when that's all you need to get your point across? With that said, I went through several months of frustration because of my relative lack of local understanding. For example, people would always tell me that I need to go para arriba [parriba] or para abajo [pabajo] to go where I needed to go. To me, up or down didn't mean much because I was unfamiliar with the relative altitudes of different villages. What seemed obvious to all the locals was a great mystery to me.

But with time I learned the subtleties of language in my rural corner of Costa Rica. Eventually, instead of saying that the rain will probably last till tomorrow morning, I learned to kick back and say "va a llover". And it felt good.