in zona sur and the northern part of zona austral the climate is temperate oceanic. here the andean cordillera intercepts moist westerly winds along the pacific coast during winter and summer months; these winds cool as they ascend the mountains, creating heavy rainfall on the mountains' west-facing slopes. the northward-flowing oceanic humboldt current creates humid and foggy conditions near the coast. the tree line is at about 2,400 m in the northern part of the ecoregion (35° s), and descends to 1,000 m in the south of the valdivian region. in the summer average temperature can climb to 16.5 °c (62 °f), while during winter the temperature can drop below 7 °c (45 °f).