The Galapagos Islands, an archipelago along the equator, present a unique climatic paradox. Despite their location, typically suggesting hot and humid conditions, these islands experience a surprisingly cool and distinct climate. This unusual weather pattern significantly shapes the islands’ extraordinary biodiversity. Understanding the forces that drive this climate helps appreciate the Galapagos’ natural wonders.
Defining the Galapagos Climate
The Galapagos Islands exhibit a subtropical climate, characterized by two distinct seasons rather than the uniform tropical conditions often associated with equatorial regions. Air temperatures range from the mid-60s to high 80s Fahrenheit (around 18°C to 30°C) throughout the year, with little to no extreme fluctuations. Average annual temperatures hover around 74.91°F (23.84°C).
Humidity levels are high, particularly during warmer months, reaching around 85%. While the islands experience rainfall, annual precipitation is relatively low. This combination of moderate temperatures, varying humidity, and limited rainfall supports both arid and surprisingly lush environments across the archipelago.
Oceanic and Atmospheric Influences
The climate of the Galapagos is shaped by the convergence of several oceanic currents and atmospheric phenomena. The cold Humboldt Current, also known as the Peruvian Current, flows northward from the Antarctic, bringing cool, nutrient-rich waters to the islands from June to November. This current lowers both air and sea temperatures, contributing to cooler, drier conditions.
Conversely, the warm Panama Current, or Panamic Current, influences the islands from December to May, bringing warmer waters from the north. This current increases ocean temperatures, which can rise to 70°F (21°C) or higher, contributing to the warmer, wetter season. The cool Cromwell Undercurrent, an eastward-flowing subsurface current, also brings deep, cold, nutrient-rich water to the western islands, supporting diverse marine life.
The Intertropical Convergence Zone (ITCZ), a band of low pressure near the equator where trade winds from the Northern and Southern Hemispheres meet, also affects the Galapagos climate. Its seasonal shifts influence rainfall patterns, contributing to the islands’ wet and dry seasons.
El Niño and La Niña events, large-scale oceanic and atmospheric phenomena, also drive climatic variations. El Niño brings unusually warm ocean temperatures and increased rainfall, while La Niña results in cooler waters and drier conditions. These events impact the islands’ weather patterns for extended periods.
Understanding Galapagos Seasons
The Galapagos Islands experience two distinct seasons. The warm and wet season, from December to May, is marked by warmer air and ocean temperatures. Daily temperatures can reach 86°F (30°C) or higher, and ocean temperatures are above 70°F (21°C). While considered “wet,” rainfall comes in sporadic, heavy showers, often in the afternoons, which clear quickly. The seas are calmer during these months, offering excellent underwater visibility.
Following the warm season, the cool and dry “garúa” season extends from June to November. This period is characterized by cooler air temperatures, averaging in the mid-70s Fahrenheit (mid-20s Celsius), and cooler ocean water, which can drop to 60°F (16°C). The “garúa” refers to a fine, misty fog that frequently blankets the highlands of the larger islands, keeping them lush and green despite drier conditions at sea level. While less rain falls, the persistent mist contributes to environmental moisture.
Climate’s Role in Unique Ecosystems
The varied climatic conditions, particularly fluctuating ocean temperatures and rainfall patterns, have influenced the evolution and distribution of its iconic wildlife. The cool, nutrient-rich waters brought by the Humboldt and Cromwell currents support abundant marine life, providing a rich food source for species like the Galapagos penguin and flightless cormorant, allowing them to thrive further north than expected for cold-water adaptations.
Marine iguanas, unique to the Galapagos, have adapted to feed on underwater algae, relying on cool ocean temperatures for their diet and basking in the sun to warm their bodies after foraging in colder water. Blue-footed boobies and other seabirds benefit from the upwelling of nutrients, which supports large fish populations, making the islands an ideal breeding ground. Giant tortoises, on the larger islands, exhibit adaptations to seasonal rainfall, migrating between arid lowlands and humid highlands in search of food and suitable nesting sites. These climate-driven dynamics illustrate the delicate balance that sustains the archipelago’s biodiversity.