The Humboldt current controls the climate of Chile kind of like the Gulf Stream which affects the climate of the UK by warming it. The Humboldt current keeps the southern part of Chile cool. Even when the sun is blazing away in the summer, the cool southerly breeze keeps the temperature down so it’s cool in the shade and warm in the sun. These southerly breezes also bring a lot of rain in the winter creating the lush vegetation of the Valdivian rain forest though not a lot of snow as the temperatures are moderate ranging around 40F in winter to 60F in summer.
The Pacific Anticyclone, a semi-permanent high pressure zone in the middle of the Pacific Ocean, shown in both maps as an open circle in the middle of the ocean (above) and as a high pressure circle in the map below, in conjunction with the mountain coastal range of Chile and the Humboldt Current make for one of the driest deserts in the world, the Atacama, in the north of Chile. And sandwiched in between the desert and the rainforest is the Mediterranean climate of central Chile which is mild and perfect for agricultural pursuits.
The Humboldt Current is slow, shallow, and cold. When the climatic phenomenon El Nino comes to the area every few years, the ocean grows warmer and the surface layer of water becomes thicker. It is then difficult for the Humboldt Current to maintain its typical upwellings, and the water becomes less nutrient-rich. El Nino this year,2014, brought an extra amount of rain causing some local flooding. The winter was warmer with northerly winds bringing the rain.