Corrections in red.  Stylistics in blue.

Weather and Deserts

It's incredible how hot the temperature is in the north of Mexico.  [Alternativa: in northern Mexico.] From months May to September the mornings start out at 27 degrees Celsius, and the days end at 32 degrees Celsius. The night isn't long enough to get cool the temperature. When the night is too hot and I can´t sleep, I turn on the air conditioner.  In Mexico electricity is very expensive, and I can´t use the air conditioner all day long, because I can´t pay the electric bill. 
In the past, 10 years ago, the temperatures in Mexico were more comfortable.  There were more woods, rivers, lagoons, and there was never a lack of rain.  Today the north of México is a big desert, without enough water.
We have to do something to return to this land to its green color -- mountains with trees, rivers with fish, lagoons with girls and beer.  Oh, sorry, I didn't mean to [alternativa: intend to] write that; I wanted to write blue Lagoons instead. 
When any of us takes a shower, we have to think that water is essential for everyone, so please take a quick shower of no more than 15 minutes.

No por nada se dice que en el norte de México ¡hay tres meses de invierno y nueve meses de infierno!