Tides & Ramps Queensland

QUEENSLAND — ONE COAST, FOUR DIFFERENT TIDES

Cairns and Brisbane get almost exactly the same spring tide: 1.844 m against 1.804 m, four centimetres apart. On neaps Cairns gets 0.478 m and Brisbane gets 1.033 m — less than half — and what is left at Cairns is not a twice-a-day tide at all. That is not a regional impression. It is sitting in the harmonic constants our own tide pages predict with, and this guide reads them out.

The basics, fast

The twelve Queensland tide pages in this guide span 1,736 km, from the Gold Coast to Karumba on the Gulf, and they are all inside one set of fishing rules — which makes it very easy to carry a tide habit north until it quietly stops working. There is no single Queensland tide. There are four regimes, and our tide roster separates them cleanly.

The rest of this guide is those four things in detail, and then what each of them does to the practical question — which ramp, and when.

What this guide will not tell you

Worth stating before anything else, because it shapes what is and is not below.

Moreton Bay and the Gold Coast: 71 km, 68 minutes, half a metre

Start with the two places most Queensland anglers actually fish, because they are close enough to feel like one region and they are not.

A tide is a sum of constituents — separate waves, each with a fixed period, each arriving at a given place with its own amplitude and its own phase. Comparing those constants between two stations is the cleanest way to see what a piece of coastline does to the water moving through it. The one that matters most is M2, the principal lunar semidiurnal tide, the twice-a-day wave that does most of the work almost everywhere.

Our Gold Coast tide page is predicted for Gold Coast Southport, inside the Broadwater behind the Seaway. Our Brisbane page is predicted for the Brisbane reference station, inside Moreton Bay. They are 71.1 km apart, and their constants say this:

StationM2 amplitudeSpring rangeNeap rangeHigh tide, relative to the Gold Coast
Gold Coast Southport (Broadwater)0.5048 m1.294 m0.725 m
Brisbane (Moreton Bay)0.7093 m1.804 m1.033 m+68 min

Moreton Bay's principal tide is 1.405 times the Gold Coast's, its spring range is 0.510 m bigger, and its high water sits 68 minutes later in the cycle. Both halves have a practical edge:

The 68 minutes is a difference in phase, not a measured travel time for a wave. It tells you where in the tidal cycle one station sits relative to the other, which is the thing you plan around. Over 71 km, and less than a quarter of a cycle, the two readings coincide. For stations much further apart the phase difference stops being a travel time at all, which is why the table below is careful about what it claims.

The whole coast, in one table

Every Queensland tide page we publish, the station it is actually predicted for, and the constants behind it. Read down the spring-range column first — that is the shape of the coast.

Two honesty notes before the numbers. First, a tide page names a place and predicts for a station, and those are not always the same point; the distance column is how far the station is from the place the page is named for, and it is the number that governs how far a prediction can drift. Second, the phase column is where a station sits in the cycle relative to Gold Coast Southport, taken to the nearer half cycle. For the near neighbours that is a delay. For Mackay, 871 km away, it is a position in the cycle and nothing more — the actual wave may well have taken a whole cycle longer to get there, and a table of constants cannot tell you which.

Tide pagePredicted forStation distanceM2 amplitudeSpring rangeNeap rangeSpring ÷ neapForm factorPhase vs Gold Coast
Gold CoastGold Coast Southport5.8 km0.5048 m1.294 m0.725 m1.780.442
BrisbaneBrisbane18.1 km0.7093 m1.804 m1.033 m1.750.366+68 min
MooloolabaMooloolaba0.6 km0.5364 m1.398 m0.748 m1.870.421−13 min
Hervey BayUrangan3.8 km1.0586 m2.816 m1.418 m1.990.255+28 min
BundabergBundaberg3.7 km0.8697 m2.327 m1.151 m2.020.289+7 min
GladstoneGladstone1.2 km1.1964 m3.244 m1.541 m2.100.252+49 min
YeppoonRosslyn Bay6.2 km1.3130 m3.612 m1.640 m2.200.255+58 min
MackayMackay Outer Harbour5.6 km1.6682 m4.558 m2.114 m2.160.257+166 min
Airlie BeachShute Harbour6.9 km1.0192 m2.768 m1.309 m2.110.392+150 min
TownsvilleTownsville2.0 km0.7454 m2.345 m0.637 m3.680.429+74 min
CairnsCairns0.9 km0.5806 m1.844 m0.478 m3.860.507+71 min
KarumbaKarumba1.0 km0.1841 m0.442 m0.295 m1.506.787−133 min

The spring-range column is the obvious story: 1.294 m at the Gold Coast, climbing to 4.558 m at Mackay — a factor of 3.52 — then falling away again to the north. Mackay is the largest principal tide in Queensland on our roster, and the difference between there and the south-east corner is not a nuance. A ramp, a creek mouth or a flat that behaves one way under 1.3 m of spring range behaves differently under 4.6 m.

The column that repays more attention is the one next to it.

North of the Whitsundays, the neap tide stops coming twice a day

Spring ÷ neap is how far the tide swings between the two halves of the lunar month. In the south-east it is under 1.8. At Cairns it is 3.86, and that number hides a change of kind rather than a change of degree.

The semidiurnal neap range is what is left when the two twice-a-day constituents work against each other: 2 × (M2 − S2). The diurnal range is what the two once-a-day constituents contribute: 2 × (K1 + O1). Where the first is larger, a neap day still has two highs and two lows, just smaller ones. Where the second is larger, the day's shape is set by the once-a-day tide — one useful rise, one useful fall, and a second pair so shallow they barely register.

Ranking our Queensland stations from south to north by the ratio of the two:

StationNeap semidiurnal rangeDiurnal rangeDiurnal ÷ neap semidiurnalShape of a neap day
Gold Coast Southport0.725 m0.572 m0.79two tides
Brisbane1.033 m0.661 m0.64two tides
Urangan (Hervey Bay)1.418 m0.717 m0.51two tides
Mackay Outer Harbour2.114 m1.172 m0.55two tides
Shute Harbour (Airlie Beach)1.309 m1.085 m0.83two tides, marginal
Townsville0.637 m1.007 m1.58one tide dominates
Cairns0.478 m0.935 m1.95one tide dominates

The crossover sits between Airlie Beach and Townsville. South of it, a neap day is a small version of a spring day and every habit you have transfers. North of it, a neap day is a different animal: at Cairns the once-a-day tide is nearly twice the size of what the twice-a-day tide has left, so the two run-outs you were planning around collapse into one that is worth fishing and one that is not.

This is the practical payload of the whole guide, so it is worth putting plainly. A plan built on "fish the run-out, there are two a day" is a south-east Queensland plan. It survives as far north as the Whitsundays. Past Townsville, on a neap, there is one — and which one it is moves through the day across the fortnight.

It also explains the hook this guide opened with. Cairns and Brisbane have essentially the same spring range because Cairns' S2 constituent is unusually large relative to its M2 — 0.3415 m against 0.5806 m, 59% — so springs add to about the same total. That same imbalance is what guts the neap, because springs add the two together and neaps subtract them. One number does two opposite jobs, which is exactly why a spring-range comparison between two ports tells you much less than it looks like it does.

The Gulf is a different ocean

Karumba is in Queensland, in the same fishing rules, and on a tide that has almost nothing in common with the east coast's.

The form factor — (K1 + O1) ÷ (M2 + S2) — is the standard way to say how diurnal a place is. Below 0.25 a tide is semidiurnal; above 3.0 it is diurnal. Every east-coast station in the table above sits between 0.252 and 0.507. Karumba sits at 6.787.

That is not "sometimes one tide a day". It is one tide a day as the normal condition, with the twice-a-day tide reduced to a ripple on it: M2 at 0.1841 m against K1 at 0.8662 m. A Gulf day has a single long rise and a single long fall, and the barramundi and threadfin fishing built around it is a fundamentally different sport from working two run-outs on the Brisbane River — even though the two places share a state, a fisheries department and, often, a boat.

Ramps: the tide restriction follows the range

All of the above would be trivia if it did not change what you can do. It changes the most basic thing there is, which is whether you can launch.

Our ramp data carries a tidal_dependent reading for each ramp — whether the ramp can only be used around a particular state of tide. Queensland has 533 ramps in our Queensland ramp set, of which 416 are on tidal water. Assigning each of those to the nearest of the eleven east-coast tide stations above, and dropping the 34 too far from any of them to belong to one (the Gulf, Cape York and the Torres Strait), leaves 382 ramps in eleven regional groups:

Region (nearest station)Spring rangeRampsTide-restrictedNot restrictedNo readingRestricted, of those with a reading
Gold Coast Southport1.294 m44835118.6%
Mooloolaba1.398 m586292317.1%
Brisbane1.804 m10113533519.7%
Cairns1.844 m361521041.7%
Bundaberg2.327 m1569040.0%
Townsville2.345 m321517046.9%
Shute Harbour2.768 m15510033.3%
Urangan2.816 m271215044.4%
Gladstone3.244 m16610037.5%
Rosslyn Bay3.612 m20713035.0%
Mackay Outer Harbour4.558 m18144077.8%

The correlation between a region's spring range and the share of its ramps carrying a tide restriction is r = 0.796 across those eleven groups. The cleaner way to say the same thing is to split the coast in two: the three south-east regions run 18.8% restricted (27 of 144 with a reading), and everything north of them runs 44.7% (80 of 179). 2.4 times the chance that the ramp you picked has a window rather than a gate.

None of that is surprising once stated — a ramp is built to a fixed height, so it strands sooner where the water moves further — but it is worth having as a number rather than a feeling, because it is the thing that turns a tide table into a departure time. At Mackay, 4 ramps out of 18 with a reading are free of a tide window. The tide is not context there; it is the plan.

A blank is missing information, not permission. 59 of the 382 have no reading at all, and every one of the 59 is in the three south-east regions, where our source data is thinnest on this field. An empty cell means nobody recorded whether the ramp strands — not that it does not. Look at the ramp, or ask locally, before treating a blank as an all-tide ramp.

What we model here, and where it stops

Stated plainly, because the honest limits of a model are part of using it.

Five ways to get a Queensland tide plan wrong

  1. Carrying a south-east run-out habit north of Townsville. The two-run-outs-a-day assumption is regional and it has a boundary, and the boundary is between the Whitsundays and Townsville. Check the actual table for the day before assuming there is a second one worth fishing.
  2. Comparing two ports on spring range alone. Cairns and Brisbane are the demonstration: the same spring tide, and neaps that differ by more than a factor of two. Spring range tells you about the biggest day of the fortnight and almost nothing about the other days.
  3. Treating the Gold Coast and Moreton Bay as one tide. They are 68 minutes and half a metre of spring range apart. That is enough to be early, and enough to misjudge how much water is actually going to move.
  4. Reading a blank ramp field as an all-tide ramp. 59 of our 382 tidal Queensland ramps carry no restriction reading, almost all of them in the south-east. Absence of a recorded restriction is not evidence of absence.
  5. Planning a Gulf trip on east-coast instincts. One tide a day, weather that overrides the astronomy, and no habitat model from us. It is the same state and it is not the same fishing.

The honest version

If you take one thing from this page.

Queensland's coast is long enough that the tide changes character along it three times, and the changes are not gradual enough to feel on the way north. Between the Gold Coast and Mackay the tide roughly triples in size. Between the Whitsundays and Townsville it stops reliably coming twice a day at neaps. West of Cape York it stops being a semidiurnal tide at all. None of that is exotic knowledge — it is in the published harmonic constants, and it has been for decades — but nobody lays it out as one coast, so a plan that works perfectly in the Broadwater gets carried to Cairns and quietly underperforms for reasons the angler never sees.

The specific, checkable version: our tide pages are predicted from the constants in this guide, every figure above is recomputed from those same constants in our test suite on every commit, and if the underlying data changes, this page fails the build rather than going quietly stale.

Built for anglers who read the water

KNOW WHICH TIDE YOU ARE ACTUALLY GETTING.

Station-specific tide times, wind, swell and water temperature for anywhere on the Queensland coast, on one screen, free to open.

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Written by
OMV
Olli-Mikael Vaittinen

Olli-Mikael Vaittinen has fished his whole life. Fifteen years of fly fishing, guiding seasons on Norway's Lakselva — his favourite Atlantic salmon river — and a blue marlin landed in Vava'u, Tonga. Founder of Fishare — the app that puts the data behind the decisions every angler makes on the water.

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