Although located on the Equator, the Humboldt Current brings cold water to the islands, causing frequent drizzles during most of the year. The weather is periodically influenced by the El Niño phenomenon which brings warmer temperatures and heavy rains.
During the season known as the "Garua" (June to November) the temperature by the sea is 22°C, a steady and cold wind blows from South and Southeast, and frequent drizzles (Garuas) last most of the day, along with dense fog which conceals the islands. During the warm season (December to May) the average sea and air temperature rises to 25°C, there is no wind at all, there are sporadic though strong rains and the sun shines.
Weather changes as altitude increases in the large islands. Temperature decreases gradually with altitude, while precipitation increases due to the condensation of moisture in clouds on the slopes. There is a large variation in precipitation from one place to another, not only with altitude but also depending on the location of the islands, and also with the seasons.
The following table corresponding to the wet 1969 shows the variation of precipitation in different places of Santa Cruz Island.