How Do El Nino and Weather Patterns Affect Whale Migration?
Whales are among the most majestic animals on Earth. Like us, they’re mammals: they breathe air, have warm blood, and are even born with a few whiskers of hair. If you’ve seen one in the wild, you know how powerful and graceful they are.
Whales also make some of the longest journeys in the animal kingdom. Knowing how whale migration works, and how weather patterns like El Niño can change it, helps you plan the best time for San Diego whale watching. Here’s what to know.
What Is Whale Migration?
Whale migration is the seasonal movement of whales between feeding grounds and breeding grounds. For many large whales, the pattern follows two basic needs:
- Feeding in cold, food-rich waters. In the warmer months, many whales head toward cooler polar waters, where krill, small fish, and other prey are plentiful. This is when they build up blubber.
- Breeding and calving in warm waters. In winter, many whales travel to warmer, calmer waters to mate and give birth. Warm, sheltered areas give newborn calves a safer start, with fewer predators like killer whales.
Many whales eat very little while they’re in their warm-water breeding grounds and live off the fat they stored up in the north. That’s why their feeding season is so important.
Different Whales, Different Migration Patterns
Not every whale migrates the same way:
- Gray whales make one of the longest migrations of any mammal. They spend summer feeding in the Arctic waters off Alaska and travel to the warm lagoons of Baja California, Mexico, in winter to give birth. The round trip is commonly estimated at 10,000 to 12,000 miles, and it takes them right past San Diego.
- Humpback whales follow well-defined routes between feeding grounds in places like Alaska and California and breeding grounds in warmer waters such as Hawaii, Mexico, and Central America.
- Killer whales (orcas) mostly follow their food. Some populations roam widely while others stay in one region.
- Sperm whales range throughout the world’s oceans. Adult males often travel alone into colder, higher-latitude waters, while females and young stay in warmer waters in social groups.
- Bowhead whales live in the Arctic all year and move with the seasonal sea ice rather than traveling to tropical waters.
- Fin whales, the second-largest animal on Earth, have more varied movements. Some populations migrate while others stay in the same area for much of the year.
Whatever the species, one thing stays the same: whales follow the food. That’s why ocean conditions and weather patterns play such a big role in whale migration.
What Is El Niño?
El Niño is a natural climate pattern that starts in the tropical Pacific Ocean and affects weather and ocean conditions around the world.
Under normal conditions, trade winds blow from east to west along the equator, pushing warm surface water toward Asia and Australia. As that warm water moves away, cold, nutrient-rich water rises from the deep along the coasts of the Americas. This process is called upwelling.
During El Niño, the trade winds weaken or even reverse. Warm water spreads back east across the Pacific toward the Americas, and upwelling slows down.
El Niño affects weather across the globe. In the U.S., it often brings:
- Warmer ocean temperatures along the Pacific Coast
- Wetter winters in Southern California and along the Gulf Coast
- Drier, milder winters in the Pacific Northwest
El Niño events usually last 9 to 12 months, and every one is a little different.
How Does El Niño Affect Marine Life?
Upwelling is the engine of the ocean food web. The cold water that rises from the deep carries nutrients that feed phytoplankton and plankton. Those feed krill and small fish like anchovies and sardines, which in turn feed seabirds, sea lions, dolphins, and whales.
When El Niño weakens upwelling, fewer nutrients reach the surface, and the whole food web shifts:
- Prey moves. Krill and baitfish may become less abundant near shore or move to cooler waters.
- Kelp forests are stressed. Kelp needs cool, nutrient-rich water to grow, so warm years can thin out kelp beds.
- Tropical species move north. Warm water brings visitors that normally live much farther south, such as tropical fish, pelagic red crabs, and rays.
- Predators adapt. Sea lions, seabirds, and whales travel farther or change where they feed to find enough food.
Does El Niño Affect Whale Migration?
Yes. Because whales follow their food, changes in ocean temperature and prey can influence:
- Where whales feed. Some whales may feed farther offshore, closer to shore, or in different areas than usual.
- When whales arrive. Migration timing can shift slightly depending on ocean conditions and food supply.
- Which species show up. Warm-water years can change the mix of marine life along the coast, sometimes bringing unexpected sightings.
The basic migration routes of species like gray and humpback whales stay the same, but El Niño can shuffle the details. That makes every season a little different and a lot more interesting.
What to Look for During an El Niño Season
You can often see the effects of warmer ocean water yourself:
- Unusual visitors. Keep an eye out for warm-water species. Off San Diego this season, we’ve been seeing spinetail devil rays, a relative of the manta ray that usually lives in warmer tropical waters.
- Shifts in whale and dolphin activity. Animals may appear in different spots or at different times as they follow their food.
- Changes in seabirds and sea lions. In some warm-water years, sea lions and seabirds have a harder time finding food, which is one reason ocean conservation matters so much.
When you’re on the water, you can help by giving wildlife plenty of space. Learn more about how to keep ocean wildlife safe when visiting San Diego’s hot spots.
What This Means for San Diego Whale Watching
For anyone who loves the ocean, El Niño makes this an exciting time to go whale watching in San Diego. Our coastline sits where cool northern currents meet warm southern waters, so changes in the ocean show up here quickly.
November has historically been a strong month for humpback whales off San Diego, and gray whale migration season follows in winter as thousands of gray whales pass our coast on their way to Baja. Add the unusual warm-water visitors this year, and nobody knows exactly what the fall and winter months will bring. That’s what makes every trip an adventure.
Frequently Asked Questions About Whale Migration and El Niño
When do gray whales migrate past San Diego?
Gray whales generally pass San Diego heading south to Baja in winter, and then head back north in late winter and spring, often with their new calves.
When is the best time to see humpback whales in San Diego?
November has historically been a great month for humpback sightings off San Diego, and humpbacks can be seen at other times of year as well.
Why do whales migrate?
Most migrating whales travel between cold feeding grounds, where food is plentiful, and warm breeding grounds, where they mate and give birth.
Does El Niño stop whale migration?
No. Whales still migrate during El Niño years. Warmer water can change where and when they feed and which other species show up, but the overall migration continues.
What is upwelling, and why does it matter?
Upwelling happens when cold, nutrient-rich water rises from the deep ocean to the surface. It feeds the plankton at the base of the food web, which supports everything from small fish to the largest whales.
Why are unusual species like devil rays showing up in San Diego?
Warmer water during El Niño can carry tropical and subtropical species farther north than usual, bringing rare visitors to San Diego waters.
Is El Niño a good time to go whale watching?
Yes. The ocean is more unpredictable during El Niño, which means more chances for surprising sightings alongside San Diego’s regular whale seasons.
See Whale Migration in Action With Next Level Sailing
Changing seasons, shifting winds, and warming waters all shape the incredible journeys whales make every year. The best way to understand it is to see it for yourself.
Join Next Level Sailing for a San Diego whale watching tour aboard the historic Yacht America. Our crew will share what we’re seeing on the water and how the season is unfolding. Book your whale watching tour today and see what the ocean has in store.
Book a San Diego Whale Watching Tour →