Located on the equator 600 miles off the coast of Ecuador, the Galapagos Islands possess a climate that is surprisingly complex. While one might expect a traditional tropical humid environment, the archipelago is actually a subtropical “oasis in a desert of warm waters,” shaped almost entirely by the convergence of three major ocean currents: the cold Humboldt, the warm Panama, and the deep, nutrient-rich Cromwell.
The Two Primary Seasons
Rather than spring, summer, fall, and winter, the Galapagos operates on a binary seasonal cycle determined by trade winds and water temperatures.
The Warm & Wet Season (December – May)
This period is characterized by tropical conditions. The Panama Current flows from the north, bringing warmer water ($76^{\circ}\text{F}$ to $80^{\circ}\text{F}$) and heating the air.
- Patterns: Days typically start with bright, intense sunshine followed by heavy but brief afternoon rain showers.
- The Feel: This is the most humid time of year. Between rain events, the sky is often a brilliant clear blue, and the air feels hot and tropical.
- Landscape: The parched lowland vegetation transforms into a lush, vibrant green.
The Cool & Dry "Garúa" Season (June – November)
The southeast trade winds strengthen, driving the cold Humboldt Current up from the south. Water temperatures take a noticeable dip ($66^{\circ}\text{F}$ to $72^{\circ}\text{F}$).
- Patterns: While there is very little actual rainfall, a persistent, fine mist known as garúa blankets the islands. The skies are often overcast, particularly in the mornings.
- The Feel: The air is cooler and fresher, often feeling more like a maritime spring than a tropical summer. The seas can be choppier during these months due to the stronger winds.
- Landscape: The lowlands turn brown and arid, while the highlands trap the mist, remaining emerald green and shrouded in fog.
Daily Dynamics and Microclimates
The climate behaves differently depending on your elevation and which side of an island you are on.
- The Transition Zones: As you move from the sea-level salt flats and cactus forests up toward the volcanic peaks, you pass through distinct microclimates. The windward (southern) sides of the islands receive more moisture, creating "scalesia forests" that feel like temperate cloud forests, even while the coast remains a desert.
- Daily Progression: In the warm season, the sun is exceptionally strong. Locals and visitors alike experience a "burn and soak" cycle: intense equatorial UV rays in the morning, followed by a cooling afternoon downpour that clears the humidity by evening.
Historical Context: The Power of El Niño
The standard seasonal cycle is occasionally upended by the El Niño Southern Oscillation (ENSO).
- El Niño Years: The trade winds weaken, and the cold currents are suppressed. This leads to abnormally high water temperatures and catastrophic rainfall. While this causes a population explosion for land birds and finches, it is devastating for marine life like marine iguanas and sea lions, as the nutrient-rich cold upwellings disappear.
- La Niña Years: These bring even colder, drier conditions than a typical garúa season, leading to massive blooms of plankton that make the ocean incredibly productive but the land exceptionally parched.
How Locals and Wildlife Adapt
Local communities in towns like Puerto Ayora are highly attuned to the trade winds. When the winds die down in December, it’s the signal that the "invierno" (winter/rainy season) is approaching. Because the sun is so powerful during the warm season, daily life often slows down during the midday heat.
Wildlife follows the weather like a clock: the cool season brings nutrient-rich waters that attract whales and whale sharks, while the warm season triggers the nesting of sea turtles and land iguanas who need the heat to incubate their eggs. For the traveler, the weather doesn't just dictate comfort—it dictates which biological drama you will witness.