More sunshine? Less rain? A breeze that turns your relaxing swim into an unexpected upper-body workout?
With El Niño expected to influence New Zealand’s weather through summer 2026/27, swimmers have good reason to keep an eye on the outlook.
The broad pattern favours drier conditions in northern and eastern New Zealand, with more frequent winds from the west and southwest. Western and southern parts of the South Island could see wetter weather. That could deliver some inviting beach days—but sunshine and smooth water don’t always arrive together. Earth Sciences NZ’s El Niño outlook
First, what actually is El Niño?
El Niño is a climate pattern involving unusually warm water in the central and eastern tropical Pacific, along with changes in winds and atmospheric circulation.
Those changes influence the weather systems reaching New Zealand. Think of El Niño as loading the weather dice: certain conditions become more likely, but it doesn’t decide what happens every day.
A generally dry summer can still have downpours. A windy season can still produce those glorious mornings when the water looks like glass.
Spring: the swimming comeback—with a possible headwind
The September–November outlook favours westerly winds, with a greater tendency towards southwesterlies from October. Unsettled, windy spells could become more prominent during mid-to-late spring.
Northland, Auckland, Waikato and Bay of Plenty have a 50% chance of below-normal rainfall over that three-month period. That means below-normal rainfall is the most likely category—not that it will rain half as much. Spring seasonal outlook
Swimmer’s lesson: Learn your wind directions. A westerly blows from the west, and whether it helps shelter your swimming spot depends on which way the beach faces and the surrounding land.
December: Bean Rock, Auckland — sunshine doesn’t flatten the harbour
El Niño may peak around November or December. If its typical pattern holds, northern New Zealand could experience dry spells alongside more frequent westerly winds.
That’s the seasonal backdrop for Bean Rock in Auckland. The weather may look lovely from your towel, while the exposed harbour has other ideas.
Swimmer’s lesson: wind and tide work together. Wind blowing against a tidal current can make waves steeper and more closely spaced. Conditions at the beach may therefore differ from those farther along the course.
Practise sighting in manageable chop with suitable support. Being able to look ahead without stopping will serve you better than repeatedly checking whether the buoy has moved. It probably hasn’t.
End of January: Island Hop, Russell — the same breeze, different bays
If El Niño remains dominant, Northland could continue to lean towards drier summer conditions. That is encouraging for Island Hop in Russell, although it is too early to predict January’s local rainfall or wind.
The Bay of Islands is a good reminder that there is no single “sea condition” for an entire coastline. One bay can be sheltered while a nearby channel catches the breeze.
Swimmer’s lesson: shelter is local. A calm starting beach doesn’t guarantee a calm route. Read the event briefing, understand where the course becomes exposed and expect the water to feel different along the way.
End of February: Legend of the Lake, Rotorua — lakes can have attitude
The northern drying tendency could continue into February, but there is no reliable basis yet for saying February will be calmer or drier than January.
At Legend of the Lake in Rotorua, the focus shifts from ocean swell to wind-generated lake waves.
Swimmer’s lesson: learn about “fetch”. Fetch is the distance wind blows across open water. With enough wind, distance and time, waves can build—even on a lake. Freshwater does not come with a flat-water guarantee.
Freshwater also provides slightly less buoyancy than seawater. If most of your training happens in the ocean, a supported lake session can help you become familiar with the different feel.
March: The Donut Swim, Whangamatā — offshore isn’t an all-clear
El Niño could remain influential into early autumn. If westerly winds feature at The Donut Swim in Whangamatā, parts of the east-facing coastline may have shelter close to land.
But there’s a catch: smooth-looking water near shore doesn’t tell the whole story.
Swimmer’s lesson: wind and swell are different. Local wind creates waves nearby; swell can travel from distant weather systems. You can have sunshine and light local winds while swell still reaches the coast.
Offshore wind blows from land towards the sea. It can make the shoreline look inviting while making a return to shore more difficult. Around islands and exposed sections, conditions can change again—so the event team’s guidance matters.
April: Lake Karāpiro Swim Fest — pack the goggles and the warm layers
Current guidance suggests El Niño could move towards neutral conditions around April–May, although the timing remains uncertain. A weakening El Niño would not automatically mean calmer weather. El Niño duration outlook
For Lake Karāpiro Swim Fest, actual wind, water temperature and autumn air temperatures will be more useful than the climate label.
Swimmer’s lesson: your swim plan should include getting warm afterwards. Have a towel and dry layers ready, particularly on breezy days. The finish line is an excellent place to celebrate; less excellent for standing around in wet gear.
Does El Niño mean warmer swimming water?
Not automatically. The warm tropical Pacific water that defines El Niño is a long way from your local swim spot.
The spring outlook separately favours warmer-than-average coastal waters around much of New Zealand, particularly the South Island. That is not a temperature forecast for every beach, and it doesn’t apply directly to our lakes. Coastal temperature outlook
Check the water temperature, not just the temperature on your car dashboard.
A promising season—with room for flexibility
From Bean Rock and Russell to Rotorua, Whangamatā and Lake Karāpiro, our NZ Ocean Swim Series visits places that respond differently to the same weather pattern.
The summer could favour drier conditions in the north, but wind may be a regular companion. These are seasonal possibilities, not forecasts for individual months or event days.
Keep training, check local conditions and water-quality advice, swim with others, and follow event updates. The goal is to become a more confident swimmer—not to win an argument with the weather.
