Cook Strait Weather & Marine Forecast
Updated Fri Nov 6, 2026
Only Saturday works; Fri and Sun are rough
Drop a pin on any spot in the world — free in the SeaLegs AI app.
Marine Forecast for Cook Strait Nov 6–8, 2026
📋 Only Saturday works; Fri and Sun are rough
NO-GO all day. NNW winds of 22-25 knots gusting to 33 and steep 4-5 foot seas at 4 seconds make for a punishing chop. A 63% chance of early rain peaks around 7:00 AM.
CAUTION: go only 4:00 AM to midnight. Easing 11-15 knot NNW winds and 2-3 foot seas make a 12-hour trip workable, but the early hours are rough. 52% chance of showers around 6:00 PM, so bring rain gear.
CAUTION: 20-21 knot NNW winds and steep 3.5-3.8 foot chop at 4 seconds through the daytime. Best timing is very early or late evening; a short outing beats a long day.
Conditions depend on the day. Saturday (Nov 7) is the best option, with a settled stretch from 4:00 AM through midnight easing to light NNW winds and small seas. Friday is rough all day with a steep, choppy NNW sea, and Sunday is borderline with persistent 4-second chop under 20+ knot NNW winds. Model agreement on wind speed is low all three days, so treat timing as uncertain.
Recent days at Cook Strait
Today’s Water at Cook Strait
Sea surface temperature and chlorophyll around Cook Strait, imaged fresh every morning. Water at the star is 13.6°C today, and chlorophyll of 0.7 mg/m³ reads as green shelf water at the spot.
Imagery: Nov 5, 2026 · rebuilt every morning
These charts show you the breaks. DeepCast reads them. A zone-by-zone AI fishing report for these exact waters — temperature edges, color changes, and structure, analyzed together.
Get the AI fishing reportSST and chlorophyll from the SeaLegs AI DeepCast satellite pipeline. Charts are a planning aid — always check the official marine forecast before making the run.
About Cook Strait
Cook Strait is the water between New Zealand's North and South Islands, and it has a reputation for rough crossings that it comfortably earns. This forecast covers the open water of the strait — wind, swell and wave height where it is exposed, not inside the shelter of Wellington Harbour or the Marlborough Sounds.
It updates every morning from the latest marine model data, and each day gets an honest GO, CAUTION, or NO-GO call — the same AI rating used in the SeaLegs AI app. Heading out of Wellington rather than across? The Wellington marine forecast is written for that trip.
Why the strait gets rough
At its narrowest the strait is only about 22 km wide, and that gap does something specific to weather: it funnels and accelerates it. The prevailing northwesterlies and southerlies are channelled straight through, so wind in the strait is routinely stronger than the same system either side of it. A regional forecast that looks unremarkable can still mean a hard crossing.
The tide makes it worse. The tides at either end of the strait run largely out of step, so strong streams push through the gap — fastest around the Narrows and off Cape Terawhiti, where the Karori Rip has a name for good reason. Wind against tide is what turns a moderate sea into a short, steep one, so read wind direction against the tide rather than wind speed alone. A southerly adds long-period Southern Ocean swell with nothing in the way.
For a small-boat crossing between Wellington and the Sounds, plan the return leg as carefully as the way over: the strait can change inside a few hours, and it is not a place to be caught deciding late.
On the water around Cook Strait
Waikawa Boating ClubCook Strait weather linksThe Picton club's own curated list of Cook Strait weather sources.waikawaboatingclub.co.nz
InterislanderCook Strait ferryThe Wellington–Picton ferry — timetables, sailing conditions and service alerts.interislander.co.nz
BluebridgeService alertsSailing disruptions and notices for the Bluebridge Cook Strait ferry.bluebridge.co.nz
Marlborough HarbourmasterHarbour noticesCurrent notices and navigation warnings for the Marlborough Sounds side of the strait.marlborough.govt.nz
Royal Port Nicholson Yacht ClubCrossing Cook Strait guideThe Wellington club's guide to crossing the strait — the Rip off Sinclair Head and Cape Terawhiti, wind, tides and the sources they check.rpnyc.org.nz
Marlborough MarinasPicton, Waikawa & HavelockMarina berths and boating information for the Marlborough Sounds side of the strait.marlboroughmarinas.co.nz
Cook Strait forecast FAQ
How is the sea at Cook Strait today?
As of Nov 6, 2026, the SeaLegs AI verdict for Cook Strait is NO-GO. Not a day to go out. NNW winds build from 17-18 knots overnight to 24-25 knots by early afternoon, gusting to 33 knots, and stay at 22-23 knots into the evening. Seas build from 3.5 feet at 6 seconds from the west to 4-5 feet at just 4 seconds from the NNW, a steep wind-wave chop that persists for 24 hours with no settled stretch long enough for a 12-hour trip. A 63% chance of rain peaks around 7:00 AM, so rain gear is needed if you are on the water at all. Model agreement on wind speed is low, so conditions could shift either way.
How rough is Cook Strait today?
The GO / CAUTION / NO-GO card at the top of this page is today's answer for the open strait, with the wind, gusts and wave height behind it. It is rebuilt every morning, and the live card refreshes in your browser. Conditions at the Narrows and off Cape Terawhiti can be rougher than the forecast point when the tide is running against the wind.
How rough is the Cook Strait crossing?
It depends almost entirely on wind strength and direction. In light winds the crossing can be calm; in a strong northwesterly or southerly the funnelling effect of the strait builds a steep, uncomfortable sea quickly, and a southerly brings long swell from the Southern Ocean on top. Check the daily wave height and wind here before you commit, and for a ferry sailing, check your operator's own sailing updates — whether a ferry runs is their call.
Does this forecast cover Wellington Harbour or the Marlborough Sounds?
No — deliberately. It is aimed at the exposed water of the strait, because that is what decides a crossing. The harbour and the Sounds are far more sheltered, and a forecast placed inside them would not tell you about the water in between.
How often is this forecast updated?
The page is rebuilt every morning from the latest model run, and the SpotCast card refreshes live in your browser. The date stamp above the outlook shows when it was last generated.
What do GO, CAUTION, and NO-GO mean?
GO means conditions are favourable for most recreational boats. CAUTION means marginal — manageable for experienced crews in capable vessels, but check the wind, tide and sea timing closely. NO-GO means conditions are hazardous for small craft and the trip is best postponed.
What is the water temperature at Cook Strait today?
As of Nov 5, 2026, the satellite-derived sea surface temperature at Cook Strait is about 13.6°C, with chlorophyll around 0.7 mg/m³ (green shelf water). The SST and chlorophyll charts on this page are rebuilt every morning from the SeaLegs AI DeepCast satellite pipeline.
More offshore forecasts
Get this forecast for your own spot
Drop a pin on any spot on planet Earth in the free SeaLegs AI app — AI marine forecasts, fishing reports, and trip planning, rated GO / CAUTION / NO-GO.
📍 Get a Marine Forecast Near You →or download directly: