The sub-tropical climate is moderated by the cool Humboldt current and the annual average temperature is 20.3°C. The hottest month is February; the coolest are July and August. Winds can make it feel cooler. The climate is moist, and some rain falls 140 days a year. March to June are the rainiest months; July to October are generally the coolest. August to December are the driest months, although heavy rains are possible year-round (much of it falling at night). Drizzles and mist are common, and a heavy dew forms overnight. Snow and frost are unknown, however. The porous volcanic rock dries out quickly, so the dampness need not deter the well-prepared hiker. (Check the weather today on Easter Island.)