The Andes block most of the moisture from the Pacific Ocean from coming in, causing it to release most of the precipitation on its western slopes and as such, most of the province is dry, with a mean annual precipitation around . Coastal areas and northern parts of the province receive a slightly higher precipitation, where it can average above a year. The Andean region receives the most precipitation with areas receiving a mean annual precipitation of in which the precipitation gradient is very strong and increases westwards. In some places, precipitation can exceed a year. Most of the Andean region has a rainfall pattern that is Mediterranean like, similar to Central Chile in which most of the precipitation falls during the winter months and summers are dry.