Because Chile stretches from the desert tropics, where solar intensity and daylight vary little over the year, to far southern latitudes where blustery maritime conditions prevail and seasonal variations can be dramatic, it’s difficult to generalize about climate. Moreover, altitude plays a major role almost everywhere.
As a rule, the Norte Grande is rainless, but cool Pacific currents and coastal fogs mean it rarely suffers oppressive heat. Rainfall increases west to east, where the precordillera and altiplano experience a summer rainy season (December–March or April), paradoxically known as the invierno altiplánico (altiplano winter) or invierno boliviano (Bolivian winter, as storms come from that direction). Violent afternoon thundershowers, common at this time of year, often make secondary roads impassable.
While arid, the Norte Chico experiences a brief winter rainy season that, after rare downpours, brings a vivid explosion of wildflowers to the desert floor. Its arid altiplano has bitterly cold winters.
The heartland has a pronounced Mediterranean climate, with wet winters and dry summers; the rainy season runs roughly May–October, the dry season November–April. About 500 kilometers south of Santiago, the city of Los Ángeles [1] marks the transition to a marine west coast climate with cool temperatures and evenly distributed annual rainfall.
Its receding glaciers sensitive to warming, Chilean Patagonia is a living laboratory for climate-change studies. While it’s the country’s wettest and coolest region, its inclemency is often overstated—despite its geographical position at the continent’s southern tip, it’s far from Antarctica. Eastern parts of it are even arid steppe, with low rainfall but frequent high winds, especially in summer.
Links:
[1] http://www.moon.com/destinations/chile/-chilean-heartland/los-angeles