Cairns Marine Forecast
Updated Fri Sep 11, 2026
Friday's gusty afternoon chop gives way to a calm weekend
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Marine Forecast for Cairns Sep 11–13, 2026
📋 Friday's gusty afternoon chop gives way to a calm weekend
NO-GO Friday: gusts up to 27-29 knots from the southeast during midday hours combine with rough 4.5-4.9 feet seas at 6s from the east overnight and in the afternoon. Unsafe conditions for recreational boating - stay ashore.
GO day with light 2-10 knot south/southeast winds and comfortable 3.5-4.3 feet seas at 6-7s from the east. Best window is 6:00 PM-11:00 PM when winds drop to near-calm 2-4 knots.
GO day with light 2-10 knot south/southeast winds (midday gusts to 26 knots) and steady 3.5-4.1 feet seas at 6s from the east. Smoothest conditions are overnight and after 6:00 PM.
Friday brings building southeast winds with strong gusts up to 29 knots during midday hours and rougher wave conditions overnight and mid-afternoon, pushing that day to NO-GO. Saturday and Sunday settle down nicely with light winds and manageable 3.5-4.3 foot seas at 6-7 second periods from the east, both rated GO throughout.
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 75.8°F today, and chlorophyll of 1.34 mg/m³ reads as nutrient-rich green water at the spot.
Imagery: Sep 10, 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 — for $4.99.
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 11, 2026, the SeaLegs AI verdict for Cairns is NO-GO. Friday is a NO-GO day, with wind staying under 12 knots from the south through southeast but gusting hard - up to 27-29 knots during the 11:00 AM to 3:00 PM window - creating unsafe puffy conditions for recreational vessels. Wave heights build to a rough 4.5-4.9 feet at 6-second periods from the east overnight through early morning (12:00 AM-7:00 AM), and choppy conditions return again from 2:00 PM to 3:00 PM. With strong gusts layered on top of building short-period easterly seas, this is not a safe day to be out on the water.
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 10, 2026, the satellite-derived sea surface temperature at Cairns is about 75.8°F, with chlorophyll around 1.34 mg/m³ (nutrient-rich green water). The SST and chlorophyll charts on this page are rebuilt every morning from the SeaLegs AI DeepCast satellite pipeline.
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