Weather & Climate of the Galápagos:
When to Go
The Galápagos are bursting with birdlife, flowing with flora, and swimming in so many marine creatures that it’s almost impossible to count them. But when it comes to seasons, there are only two: the hot/rainy season and the cool/dry season, also known as the garúa.
During the garúa season, which typically lasts from July through December, temperatures are lower than they are during the rest of the year. Cold waters come up from the Antarctica region, carrying with them the makings for a subtropical — rather than tropical — climate. A fine, misty rain (or garúa) blankets the tops of the islands, which turn lush and emerald green.
The hot/rainy season runs from January to June. In the first three months of the year, the annual rains arrive; they are strong but of short duration. Temperatures rise, and sunny days are frequent. Warmer waters head south from Panama and Columbia, making this — for some — a favorite time for snorkeling.
However, the varied natural changes the two seasons bring to the appearance and fauna of the islands mean that there’s never a bad time to see and visit the Galápagos. The “peak season” is sometimes described as mid-June through early September and from mid-December through mid-January. But since the Galápagos National Park Service works with tour providers to coordinate every ship’s itinerary and has restrictions on the number of visitors to each island at any one time, you will never feel as if you’re one in a throng of people. At any time of the year, you’ll be sure to feel as if the islands are yours alone — or yours and a few good friends’ — to enjoy in peace and natural solitude.
To help you decide which time of year would be best for your visit, read more below:
January through June
During the hot/rainy season in the Galápagos, the water and the air temperatures are warmer, but it drizzles for a short period of time almost daily. Strangely, however, this is also the sunniest time of year, making your visit to the islands now extremely enjoyable.
In late March and April, as the rains start to dissipate, flowers blossom. The ocean is clear and warms to the high 70s or even to 80 degrees Fahrenheit; air temperatures may reach the low 90s. Because of the warmer water, some find swimming and snorkeling to be more to their liking during these months. On the other hand, there aren’t as many fish to see as there are later in the year.
Another benefit of traveling to the Galápagos at this time of year is that the ocean is much calmer, so you'll have less chance of getting seasick. The waters start to get a bit choppy in July and are at their roughest from August to October.
July through December
During the garúa season, the Humboldt Current makes it way up to the Galápagos from the southern end of South America. It brings cold water and cold weather, but it also creates a sea rich in nutrients and plankton, which attracts fish and birds.
Stratocumulus clouds sail in the skies over the Galápagos at this time of year. They accumulate around the tops of volcanoes and wait there — sometimes for weeks on end. Although the higher reaches of the islands may get so wet and fog enshrouded that they become bogs and moorlands, lush, fertile Moist Zones are also created. The lowlands remain arid, however, and only receive any appreciable rain during El Niño periods. Because the prevailing wind in the Galápagos is from the southeast, the south sides of the major islands are much moister than the north sides, which lie in a rain shadow.
Daytime temperatures during these months seldom exceed 75 degrees Fahrenheit, and water temperatures range from the low 70s throughout most of the islands down to about 60 degrees on the west side of Isabela. These cool waters bring a plankton bloom. Some experienced divers prefer this time of year to visit the Galápagos. There are more fish in the sea now — and more seabirds searching for them.
On Española, waved albatrosses arrive and stay until December. Galápagos penguins come for the colder water and the abundance of fish, so you’re more likely to see them here during this season. On Genovesa Island, elusive short-eared owls mate. Blue-footed boobies also mate now, so it won’t be difficult to observe their courtship ritual: a posture known as the “skypoint.”
Average Air and Water Temperatures by Month
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Wildlife Highlights by Month
In the first month of the year, you’ll experience generally sunny days with a chance of tropical, afternoon showers. Both air and water temperatures begin to rise; averages are 84 degrees Fahrenheit for the high, with the ocean registering about 74 degrees.
February is very much like January, only with slighter warmer air and water temperatures.
March is the rainiest month of the year in the Galápagos, with an average of two inches of precipitation, falling sporadically.
Tropical rain showers may still be frequent in April, but the monthly average of precipitation drops to 1.5 inches. Air temperatures begin to slightly cool.
The tropical rain showers taper off, and the monthly precipitation average reaches less than an inch. The air temperature continues to cool, as does the water temperature.
Temperatures continue to drop, and rain showers become rare.
July is the beginning of the garúa season. Temperatures continue to cool down, sometimes falling into the 60s. Rain showers are rare. Water temperatures also begin to cool, with an average of 72 degrees Fahrenheit.
August is the coolest month of the year in the Galápagos, with highs in the mid 70s. Water temperatures are at their coolest, too, with an average of 68 degrees Fahrenheit. There is very little rain.
This is the peak of garúa season. Birds and land animals are very active.
The garúa season continues. Water temperatures begin to warm, with an average of 71 degrees Fahrenheit. Summits on the islands are clear, but the coasts may be covered in low-hanging haze.
Air and water temperatures continue on an upward climb. Seas are calm, and there is good visibility for snorkeling.
Rain showers are still rare, as the garúa season comes to an end. The Galápagos begin to green. Temperatures rise, with an average high around 80 degrees Fahrenheit and a low at about 70. Water temperatures warm to about 74 degrees Fahrenheit.
Forces Important to Understanding Galápagos Climate:
Ocean Currents, Niño Flow and El Niño Years, and Upwelling
Climate in the Galápagos is almost entirely determined by the ocean currents and whichever one is prevalent at the time — and where each island is relatively located within that current. The currents, in turn, are influenced by the trade winds that push them.
Because the archipelago is situated at an unusual geographical spot where several ocean currents — the cold Humboldt Current from the south, the tropical Panama Current from the northeast that brings with it the sometimes devastating El Niño events, and the cold South Equatorial Current that flows westward into Galápagos waters — meet, they are remarkably cool and dry. Other currents also have an influence, such as the cool Peru Coastal Countercurrent (also known as the Peru Flow) and the cold Cromwell Current (also known as the South Equatorial Countercurrent) from the west. The currents not only create cooler than normal temperatures but strong, unpredictable tides between the islands. This mix of cooler water temperatures and a nutrient-rich upwelling give the Galápagos Islands their unique climate — and an abundance of marine life.
Southeast trade winds blow towards the Equator from May to December. When they retreat southwards, then so does the surface current. An influx of much warmer water from the north then arrives, which brings high humidity and heavy tropical rains to the islands. This warm water is known as El Niño.
For most of the year, the cold, nutrient-rich Humboldt Current sweeps northward from Antarctica, hugging the coast of South America. Where the coastline changes contour at the northern tip of Peru, the Humboldt (pushed by trade winds from the southeast) keeps on its original northwesterly course, arcing its way across the Pacific and heading right for the Galápagos Islands. Cool water then washes over the archipelago (about 64 to 72 degrees Fahrenheit at the surface).
Typically, the higher the elevation, the colder the air. But the cold, massive Humboldt Current cools the air directly above it. So warm air sits on top of the cooled surface air, forming what’s called an “inversion layer.” This inversion continues until an equilibrium is reached; in the Galápagos, this occurs at one thousand to two thousand feet above sea level.
The inversion layer contains a heavy concentration of moisture droplets that have evaporated from the ocean. On some of the islands, highlands intercept the inversion layer and condense this moisture. Then, a continuous mist is formed, called a garúa. Thus while the highland areas are kept lush and green by the garúa mist, the lowland areas of these islands (as well as entire low-elevation islands) are bone dry. This, then, is known as the cool/dry season, even though there is more precipitation at this time of year. It may be that this was originally referred to as the “dry season” because the garúa made it difficult for settlers to collect water.
The Humboldt Current is strongest in September, causing a choppy surface. But these last months of the year are a good time for Galápagos green turtle sightings.
Even though they are located on the Equator, the Galápagos Islands are classified as subtropical rather than tropical. However, the northern islands are almost tropical, because they are less affected by the cold waters of the south. It is the southern islands that feel the full effect of the cold ocean stream of the Humboldt Current.
Around December, the southeast trade winds slacken, no longer driving the Humboldt Current toward the Galápagos. This allows the warm waters of the Panama Current, flowing south and once again heading right at the Galápagos, to be dominant through May. Thus, the island waters are warmed (to about 75 to 80 degrees Fahrenheit at the surface), no longer cooling the air to a significant degree, and the inversion layer breaks up. This phenomenon is called an El Niño, which is Spanish for “the child” because the condition begins around Christmas.
The skies are generally clear, with the exception of occasional strong but short rains from which settlers were able to catch water, giving this season the characterization of the “hot/rainy season,” which lasts from January to June. What’s a bit confusing is that the highland areas receive more moisture from the garúa during the dry season than they do from rainfall during the rainy season.
The waters of the Panama Current have far less nutrients than the Humboldt Current. They thus provide the best visibility underwater for diving and snorkeling.
South Equatorial Current
The South Equatorial Current is the major surface current in the tropical Pacific. It flows west between roughly five degrees north and ten degrees south of the Equator.
Niño Flow and El Niño Years
There are two types of El Niño events in the Galápagos. The “Niño Flow” is an annual, normal slackening of the Humboldt Current; or more accurately, a seasonal reduction in the upwelling along the South American coast. It typically occurs around Christmastime, hence the name Peruvians use: El Niño or “the Child” for the Christ Child. Periods when this phenomenon occurs earlier or is more intense are known as “El Niño years.”
In an El Niño year, the southeast trade winds fail to show up, causing the Panama Current to stay in the islands, drastically warming the waters of the Galápagos. Upwelling stops, driving coldwater species to migrate or to go deeper. This influences the entire food chain and the breeding cycle of many species, including Galápagos penguins and marine iguanas, which feed off the upwelling.
These types of El Niños, which occur every two to fifteen years, can be intense or even severe; they are associated with not only higher sea surface temperatures but more rainfall. When the Pacific weather system is severely disrupted and the rains last for six to nine months, species that depend upon the sea for their food suffer huge losses. In the El Niño of 1997–98, an estimated 90 percent of Galápagos sea lion pups and 76 percent of the dominant males died from starvation because of the lack of their staple diet of sardines. In contrast, land species such as birds, butterflies, and land iguanas flourished. And plants seem to thrive during El Niño years — some that may have failed to flower for long periods now will due to the excess water.
The variation in rainfall that comes during an El Niño year can be dramatic. During 1982–83, over an eight-month period, more than 118 inches of rain was recorded in Academy Bay on the south side of Santa Cruz. (In contrast, the average annual rainfall in Academy Bay for the years 1965–70 was only eight inches.) Over 216 inches was recorded at Santo Thomas in the highlands of Isabela.
The cause of such major El Niño events is unknown. While they can be expected to occur in somewhat regular intervals, over the past hundred years, no events of the magnitude of 1982–83 or 1997–98 have previously been recorded. It is postulated that global warming may be involved.
Many of the birds and animals in the Galápagos depend on the ocean for food. Seabirds and marine mammals (whales, Galápagos sea lions, and Galápagos fur seals) eat a variety of fish and squid, which in turn, feed on tiny animal plant life (plankton) near the surface.
In order for plants to grow in the ocean, they need sunlight and nutrients.
In nature, typically these nutrients are produced by the decomposition of organic materials, such as what happens on a forest floor. In the ocean, such organic materials sink to the bottom. This makes for an ocean floor that is rich in nutrients; but, unfortunately, there is little or no light.
On the other hand, on the surface, you have plenty of light, but no nutrients. Consequently, what’s needed is a “pump,” one that will churn the waters and force the nutrients to the top.
There are actually a few places in the world where nature provides such a pumping system. It’s called an upwelling (or “Equatorial Undercurrent”). Upwelling frequently occurs when two or more ocean currents converge in the proximity of land, thus agitating the waters. The Galápagos, where there are at least five ocean currents intersecting, is one of these “pumping” sites which nature provided.
In the Galápagos, the upwelling takes place with Antarctic waters. As deep waters enter the Antarctic, they freeze, becoming saltier and denser. This denser water sinks and, along with the surface water, moves north from the continental plate. The water is replaced by nutrient-rich, southward moving water between the surface and bottom layers. That southern moving water — with its rich nutrients — rises to the surface and stimulates the growth of phytoplankton. The phytoplankton is consumed by zooplankton and other krill, which in turn are consumed by fish and whales.
As these rich Antarctic waters are pulled away from the shore, they become the Antarctic Circumpolar Current. Part of this current is broken off at the tip of South America to form the Humboldt Current. The Humboldt Current continues up the coast of South America and reaches the Galápagos Islands from July to December.
In El Niño years, the cold waters from the Antarctic do not reach the islands. Due to the lack of upwelling, the food chain is broken, affecting species such as flightless cormorants, Galápagos penguins, and marine iguanas.
Examples of Fahrenheit to Centigrade Conversions
To convert Centigrade into Fahrenheit, multiply the Centigrade temperature by 1.8 and add 32. To convert Fahrenheit into Centigrade, subtract 32 from the Fahrenheit temperature and divide by 1.8. The following are some examples of conversions between the two systems: