NOAA’s Climate Prediction Center kept its El Niño Advisory in place on October 8, 2026, and the outlook now calls for a strong-to-very strong El Niño to last through the core of Hawaiʻi’s winter. That matters for anyone holding dates between November and March, but not in the way a phone forecast matters. El Niño shifts seasonal odds across a whole winter. It does not say whether a particular Tuesday at Hanalei will be dry, or whether the north shore will be swimmable on the morning you arrive.

The separate October 15 Hawaiʻi seasonal outlook adds a more specific rainfall signal. Use this guide to separate the ENSO discussion from the local seasonal outlook, then build a trip around odds without pretending they are promises. The next ENSO discussion is scheduled for November 12, 2026; the next Hawaiʻi seasonal outlook follows on November 19.

The October 8 CPC discussion says El Niño continues to strengthen, and a strong-to-very strong El Niño is likely through January–March 2027, with the chance remaining greater than 83%. The same discussion reports a separate figure: an 83% chance that the October–December three-month Relative Oceanic Niño Index (RONI) reaches +2.5°C or more, a level that would exceed every event in the record back to 1950.

Those two numbers look alike and measure different things. The first is the probability of a strong-to-very strong event through January–March 2027. The second is the probability a specific three-month index crosses a record threshold. Neither is a probability of sunshine in Kāʻanapali or Poʻipū, and neither should be read as one. CPC’s own wording is the one to carry forward: with an event of this size, impacts consistent with El Niño are more likely, though not guaranteed.

The CPC Hawaiʻi seasonal outlook issued October 15 assigns Hilo, Kahului, Honolulu and Lihue each a 75% probability of below-normal three-month rainfall totals for both December 2026–February 2027 and January–March 2027. For November 2026–January 2027, the probabilities are 70% at Hilo, 60% at Kahului and 50% at Honolulu and Lihue.

These are station forecasts relative to each station’s seasonal rainfall categories. 75% does not mean 75% less rain, 75% sunny days, or a 75% chance of a dry vacation. Nor does it rank entire islands or individual resorts. NOAA’s October 15 U.S. Winter Outlook also favors a dry signal for Hawaiʻi, while giving equal chances of below-, near- or above-average winter temperatures.

NWS Honolulu’s October 22 wet-season briefing covers October 2026 through April 2027. If the below-normal rainfall forecast verifies, it anticipates drought developing in many areas during the second half of winter and potentially worsening through spring. It also flags a higher potential for out-of-season wildfires as vegetation dries, with strong winds capable of increasing the danger. These are conditional seasonal risks, not a report of a current fire or a restriction at your destination.

For your stay, conserve water and check your accommodation’s current water-use instructions, especially if it relies on rainfall catchment. The briefing identifies catchment and surface-water supplies as sensitive to rainfall deficits. A drier outlook is a reason to limit unnecessary water use, not a promise of uninterrupted outdoor plans.

Keep both dry-weather and heavy-rain contingencies in the same trip plan. NWS warns that flash flooding can still happen during drought: do not drive through fast-flowing water or walk across flooded streams. Check the local forecast and current Conditions before the outing, and follow official warnings and closures. Use the seasonal outlook for preparation; use current local guidance to decide whether to go.

The most useful plain-language reference is NOAA’s historical analysis of ENSO and Hawaiʻi, published in May 2022. It is historical work on records from 1951 onward, not a forecast for this winter, and it should be read that way.

That historical analysis describes November through April as Hawaiʻi’s wet season. In most winters the trade winds are periodically interrupted by larger systems, including Kona lows and fronts, that bring rain even to leeward coasts that stay dry under normal trades. In a typical El Niño, the Pacific jet stream extends farther east and places the islands under sinking air, which favors below-average winter rainfall, with the signal strongest in January and February. The Honolulu record shows that drier tendency on average, and a statewide index points the same direction. The analysis is explicit that the tendency does not hold every season.

Two cautions follow. Rainfall in Hawaiʻi changes enormously over short distances, and windward slopes and leeward coasts have different rainfall patterns. And a tilt in seasonal odds is not a reason to cancel a windward waterfall hike or write off a rainy-side stay. A leeward base is a sensible default for a sun-first trip in any winter; the seasonal outlook does not settle the weather for any given week.

The same NOAA analysis notes that El Niño is sometimes associated with bigger swells because of the extended jet stream. That is a tendency across a season, not a forecast for your dates, and it is not a reason to expect a show every day.

The State of Hawaiʻi’s ocean safety guidance is the part to act on. From November through April, north- and west-facing shores can see extremely high surf driven by powerful North Pacific storms, and swimmers of any skill level should stay out of the water during high surf. That rule applies in every winter, El Niño or not. A large north-shore swell also says nothing automatic about south-shore conditions; check those separately rather than assuming the other side is calm.

For a current read, use the Hawaiʻi ocean report in the days before a beach day and defer to lifeguards on site. If the goal is watching rather than swimming, the Oʻahu North Shore winter surf guide covers viewing plans and the usual seasonal pattern.

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NOAA’s Hawaiian Islands Humpback Whale National Marine Sanctuary describes the season as generally November through May, with the usual peak from January through March and limited numbers possible in other months. Nothing in the October El Niño outlook changes how to plan around that. Travelers locked into November or early December should treat a sighting as possible, not promised. Travelers choosing dates around the whales should build around January, February, or March.

The October CPC discussion does not forecast whale sightings or the sea conditions on a particular boat trip. Do not use its El Niño probabilities as a promise of more whales or a smoother ride. Use our whale watching season preview for month, island, and harbor planning, then our whale season guide for typical monthly activity patterns, not live sightings. Check the day’s marine forecast and the operator’s advice before a boat trip.

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Choose your lodging around the trip you want, leave room to move an outdoor day, and use local forecasts to choose the actual outing. Those decisions work on different timelines.

For a sun-first trip, consider a leeward base; for a trip built around a particular windward town, weigh that location against the drives you plan. A seasonal rain tendency is useful context, but it does not guarantee a dry hotel or settle which island fits you. Our guides to January and February put the winter weather alongside other planning choices.

If you are booking this winter: use the new rainfall outlook as background, then compare the location and change terms of the stays you actually want. Keep a rain layer and an alternative outdoor window in the plan. Our Hilo rainfall totals and rainy-days explainer shows why less total rain need not mean fewer days with rain. A seasonal dry signal does not remove Kona-low, flooding or high-surf risk.

Leave one outdoor day uncommitted if your schedule allows. It may give you room to move a beach visit or scenic drive when conditions change. Check cancellation and change terms before treating a reserved boat trip or permit as flexible; an empty day does not make a fixed reservation transferable. One spare day cannot protect every plan from a prolonged weather event.

In the days before an outing, check the local weather forecast, Ocean Report, and Conditions. Check again that morning, respect closures and warning signs, and follow lifeguards’ advice at the beach. If conditions rule out the activity, use the open day or choose a different plan. Recheck CPC’s November updates for seasonal context and keep making the daily decision from current local guidance.