Cairns Marine Forecast
Updated Tue Sep 29, 2026
Three solid GO days with light winds and manageable seas
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Marine Forecast for Cairns Sep 29 – Oct 1, 2026
📋 Three solid GO days with light winds and manageable seas
A good boating day with light morning winds building to near 10 knots by midday, with gusts up to 27 knots from the southeast during the 10:00 AM-3:00 PM window. Seas stay comfortable all day at 3.5-4.1 feet with 6-7 second periods from the east. Early morning or evening offers the calmest conditions.
The best day of the period, with light winds most of the day and a standout calm evening window from 6:00 PM to 10:00 PM featuring just 2-3 knot winds. Midday gusts still reach 25-26 knots from the east-southeast, but seas stay a manageable 3.7-4.2 feet at 6-second periods from the east throughout. Great flexibility for scheduling a trip.
A good day overall, with very light winds overnight giving way to a midday-afternoon peak near 9 knots and gusts to 25 knots from the southeast. Seas build slightly to 4.3-4.5 feet at 6-second periods from the east during the afternoon, the largest of the period but still manageable. Morning and evening hours offer the calmest conditions.
Tuesday through Thursday all offer good boating conditions, with light single-digit-to-low-teens winds from the south to southeast and consistent 3.5-4.5 foot seas at 6-second periods from the east. Winds build modestly midday each day but stay within comfortable limits for recreational vessels, and gusts, while occasionally reaching into the low-to-mid 20s, are brief and manageable.
Recent days at Cairns
Today’s Water at Cairns
Sea surface temperature and chlorophyll around Cairns, imaged fresh every morning. Water at the star is 74.1°F today, and chlorophyll of 0.2 mg/m³ reads as blue-green transition water at the spot.
Imagery: Sep 29, 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 Cairns
Cairns is the gateway to the northern Great Barrier Reef, and almost every trip out of Trinity Inlet means crossing open water from the bay to the outer ribbon reefs. Reef fishos chase coral trout, red emperor, nannygai, and Spanish mackerel, while the heavy-tackle fleet works the ribbons for giant black marlin through the September–December peak — but the run out is what decides the day.
The forecast here is built around the one thing that makes or breaks a Cairns trip: the south-east trade winds against the open-water crossing to the reef. Each day gets rated GO / CAUTION / NO-GO — the same AI rating used in the SeaLegs AI app.
Reading conditions off Cairns
In the dry season the SE trades set the sea state, and there's a world of difference between 10–15 knots and a reinforced 20–25. The reef sits a long way off the beach, so even a moderate trade stacks up a short, sharp chop across the crossing well before you reach the shelter of the outer ribbons. Watch the trend, not just the number: trades that freshen through the week leave little margin on the run home.
Time your crossing to the wind, not just the tide. The trades commonly ease overnight and through the early morning, then build into the afternoon, so an early start off Trinity Inlet usually buys the flattest water. In the summer wet season the pattern flips to monsoon troughs and cyclone risk, when a settled forecast can deteriorate fast — check it the morning you leave, not the night before.
Cairns forecast FAQ
How is the sea at Cairns today?
As of Sep 29, 2026, the SeaLegs AI verdict for Cairns is GO. Tuesday is a GO day with generally favorable conditions throughout, though model confidence is moderate (72%) with some disagreement on wind speed specifics. Winds stay light in the early hours at 2-5 knots from the south-southwest/south, building to a peak of around 10 knots from the east-southeast by midday with gusts reaching 25-27 knots between 10:00 AM and 3:00 PM - the bumpiest stretch of the day. Seas remain steady and comfortable throughout at 3.5-4.1 feet with organized 6 to 7-second periods from the east, easing again in the evening as winds drop back to single digits.
What makes a good day to run the reef out of Cairns?
It comes down to the south-east trades against the open-water crossing from Trinity Inlet to the outer reef. Light-to-moderate trades under about 15 knots usually mean a comfortable run and a GO; a reinforced 20-plus trade builds a short, steep chop across the crossing and pushes the day toward CAUTION or NO-GO. Because the trades tend to ease overnight and build in the afternoon, an early departure generally gives you the flattest water for the run out and back.
How accurate is this Cairns marine forecast?
The outlook is generated from the latest marine model data and rated GO, CAUTION, or NO-GO by the same AI engine used in the SeaLegs AI app. It's a planning aid, not a substitute for the official Bureau of Meteorology (BoM) marine forecast and any current warnings — always check those before heading out.
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 exactly 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 and sea timing closely. NO-GO means conditions are hazardous for small craft and the trip is best postponed.
Can I get a forecast like this for my own spot?
Yes. In the free SeaLegs AI app you can drop a pin anywhere on Earth — your local ramp, a favourite mark, or a spot well offshore — and get the same AI-rated marine forecast and trip planning.
What is the water temperature at Cairns today?
As of Sep 29, 2026, the satellite-derived sea surface temperature at Cairns is about 74.1°F, with chlorophyll around 0.2 mg/m³ (blue-green transition water). The SST and chlorophyll charts on this page are rebuilt every morning from the SeaLegs AI DeepCast satellite pipeline.
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