Mackay tide times

Mackay's tide is big: about 3.7 metres from low to high on an average day and around 4.6 metres at springs, with the highest astronomical tide 6.62 metres above LAT in Queensland's tables. The gauge is at the Outer Harbour, about eight kilometres north-east of the city centre.

Moving water sets the hour here. The Mackay Outer Harbour tide gauge, 8.1 km from the middle of Mackay, carries 50 harmonic constants from its record. Mean range is 3.65 m, and the form factor — diurnal constituents over semidiurnal — is 0.26, which is mixed, mainly semidiurnal water.

Tide times and heights at Mackay

The curve answers a question the table cannot. A table gives the minute of high tide; the curve gives the hour you can actually get out — the stretch between one turn and the next that no row describes, and on a mixed, mainly semidiurnal coast that is most of the fishing day.

What the tide does at Mackay

North towards the Whitsundays the tide runs later. Maritime Safety Queensland's tidal planes put high tide at Laguna Quays Marina 30 minutes after Mackay Outer Harbour and low tide 25 minutes after; at Halliday Bay high tide is 9 minutes later and low tide 23, while at Carlisle Island both stay within two minutes of the harbour.

With this much water moving, a minute matters more than on a small-tide coast: around mid-tide on an average spring the level here changes by a little over a metre in an hour. The gauge record behind the constants spans 1960 to 2022 with gaps, and fifty-four years of it went into the TICON-4 analysis.

What the heights are measured from

Every height here is metres above Lowest Astronomical Tide, the port and chart datum Queensland has used since 1994. It is fixed — set from the tides of 1992 to 2011 and written LAT(1992) — and it is not the sea bed: it is a level placed so low that the astronomical tide alone seldom gets beneath it. For the 2026 predictions, Maritime Safety Queensland puts mean sea level at Mackay Outer Harbour 3.09 m above that line, from gauge records for Jan 1994 to Dec 2022, and our tables stand on that same figure.

The useful consequence is that the soundings on a Queensland chart are measured from the same datum. Four metres charted with a 1.2 m tide is about 5.2 metres of water at that moment. When a low does dip below zero, Queensland's tables mark it with a minus sign, and a real sea well under zero is usually wind and pressure at work rather than the Moon.

Why the two high tides differ at Mackay

The two high tides of a day are not twins at Mackay. On average the higher one stands 0.39 m above the mean high water, and the gap follows the Moon's declination rather than its phase: it is widest when the Moon stands far north or south of the equator and nearly closes when the Moon crosses it, about every two weeks. On those days one of the four daily turns can shrink to a few centimetres, and the water all but stands still.

The Moon sets the rhythm and the Sun decides how hard it lands. When the two pull in line the ranges stack; when they pull across each other the range collapses. At Mackay that puts the spring range near 4.56 m against a neap range near 2.11 m — a factor of 2.16 between the strongest and the weakest tides of the fortnight.

Both figures come from the gauge's own constants rather than from the fortnight on this page, which is why they do not move when the table is rebuilt. Maritime Safety Queensland's tidal planes give Mackay Outer Harbour a mean high water springs of 5.35 m and a mean low water springs of 0.79 m — a published spring range of 4.56 m against 4.56 m from the constants, and that agreement is a check on the arithmetic rather than a coincidence. The same calculation at Gold Coast, QLD gives a mean range of 1.07 m against 3.65 m here — the same Moon and Sun acting on a different stretch of coast, with a different amount of water moving through it.

How close these numbers are to the Bureau of Meteorology

These are not the Bureau of Meteorology's predictions. The gauge's record has been analysed into 50 harmonic constants in TICON-4 — the amplitudes and phases of the periodic pulls that make up the tide here — and we synthesise the curve from them, standing it on the mean sea level Queensland publishes. Saying so is easy; the numbers that follow are the part worth reading.

Against the Bureau's own predictions, published in the Queensland Tide Tables for January 2024, all 120 high and low tides found their pair. Half fell within 4.7 minutes of the Bureau's time and nine in ten within 11. The worst was 15 minutes. The worst height difference was 3.3% of the day's range. Two different analyses of the same gauge sit behind those numbers — ours from TICON-4, the Bureau's from its own — and minutes rather than seconds is what that costs.

The second check is on the levels. Maritime Safety Queensland publishes the highest astronomical tide at Mackay Outer Harbour as 6.62 m; our synthesis over the full 18.6-year lunar cycle, on the same mean sea level, gives 6.55 m, 7 cm apart.

A month of comparison is not a year, and a gauge with a big, awkward range does worse than an open coast; where that shows, the page says so, and the method behind every number on this site is written out.

When a tide table is not the right tool

A tide prediction is astronomy, and the water is weather as well. Wind and barometric pressure move the real level against the predicted one, and in a cyclone the storm tide can stand a metre or more above it — Queensland issues storm tide warnings for exactly that. The numbers here are also the gauge's water, not the water up a creek or a river, where the same tide arrives later and smaller. For navigation, the reference is the Queensland Tide Tables.

Sources. Mean sea level, tidal planes and highest astronomical tide: Maritime Safety Queensland, Department of Transport and Main Roads, Queensland Tide Tables, licensed under Creative Commons Attribution 4.0 Australia. The Department of Transport and Main Roads gives no warranty of any kind whether express, implied, statutory or otherwise in respect to the availability, accuracy, currency, completeness, quality or reliability of the information or that the information will be fit for any particular purpose or will not infringe any third party Intellectual Property rights. The Department of Transport and Main Roads liability for any loss, damage, cost or expense resulting from use of, or reliance on, the information is entirely excluded.

Comparison predictions: tidal prediction tables © Commonwealth of Australia, Bureau of Meteorology, as published in the Queensland Tide Tables. This product is based on Bureau of Meteorology information that has subsequently been modified. The Bureau does not necessarily support or endorse, or have any connection with, the product. In respect of that part of the information which is sourced from the Bureau, and to the maximum extent permitted by law: (i) The Bureau makes no representation and gives no warranty of any kind whether express, implied, statutory or otherwise in respect to the availability, accuracy, currency, completeness, quality, reliability or suitability of the information or that the information will be fit for any particular purpose or will not infringe any third party Intellectual Property rights; and (ii) the Bureau’s liability for any loss, damage, cost or expense resulting from use of, or reliance on, the information is entirely excluded.

Tide is the hour; it does not tell you which hour is worth taking. The reasoning behind solunar windows — and what they are worth on a coast where moving water already sets the hour — is in best fishing times. Which fishing apps carry tide tables at all, and how they say where their numbers come from, is a separate comparison.

The nearest gauges this site carries are Townsville, QLD (1.7 m), Cairns, QLD (1.39 m), Brisbane, QLD (1.51 m) and Gold Coast, QLD (1.07 m), and the full list with the gauge behind each place is on the Australian tide times index.