St. Petersburg, FL tide chart

St. Petersburg reads its tide at NOAA's gauge on the downtown waterfront, on Tampa Bay: a mixed tide with a mean range of about 1.6 feet, and two lows a day that are often well apart — the lower low averages about 0.4 foot below an average low.

Moving water sets the hour here. The NOAA gauge 1.7 km from the middle of St. Petersburg publishes 37 harmonic constants. Mean range is 1.6 ft, and the form factor — diurnal constituents over semidiurnal — is 1.41, which is mixed, mainly semidiurnal water.

Tide times and heights in St. Petersburg

The curve answers a question the table cannot. A table gives the minute of high water; 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 St. Petersburg

The bay delays the Gulf's tide by hours. NOAA's predictions for Clearwater Beach, on the open Gulf thirty kilometres to the north-west, run about two and a half hours ahead of St. Petersburg, and Port Manatee, in the lower bay, about fifty minutes ahead.

By this page's own synthesis over the nineteen-year cycle the water at the waterfront ranges from about one foot below mean lower low water to about three feet above it.

What the heights are measured from

Every height here is feet above mean lower low water. That reference is not the sea bed and not the water under your keel — it is the average of the lower of each day's two low waters, taken over a nineteen-year epoch. A printed low water of 1.3 ft means the surface stands 1.3 feet above that line, not that there is 1.3 feet of water.

The useful consequence is that NOAA measures its charted depths from the same line. A sounding of four feet with a 1.3 ft tide is about 5.3 feet of water at that moment, and the same sounding at a −0.4 ft tide is about 3.6. Mixing the two references is the single most common way to read a tide table wrong.

Why the two high waters differ at St. Petersburg

The two high waters of a day are not twins at St. Petersburg. On average the higher one stands 0.28 ft 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.

That is also why spring and neap tides explain less here than on a semidiurnal coast. The diurnal constituents carry a large share of the water — the form factor is 1.41 — so the Moon's distance from the equator matters about as much as its phase. The same calculation at Juneau, AK gives a mean range of 13.74 ft against 1.6 ft here — the same Moon and Sun acting on a different coast, with a different amount of water moving through it.

How close these numbers are to NOAA

These are not NOAA's published predictions. The station publishes 37 harmonic constants — amplitudes and phases of the periodic pulls that make up the tide here — and we synthesise the curve from them. Saying so is easy; the number that follows is the part that is worth reading.

Against NOAA's own predictions for August 12–19, 2026, every one of the 31 high and low waters matched, with an average difference in time of 1.06 minutes and a worst case of 2.63. The worst height difference was 0.9% of the day's range. That is the whole claim, and it is smaller than the width of the pencil line on a printed table.

Two limits belong with that number. It is a week of comparison, not a year, and it is this station: the same method run at a station with a big, awkward range does measurably worse, and our own worst case on the grid is off by minutes rather than seconds. Where that is true, the page says so, and the method behind every number on this site is written out rather than summarised.

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 printed one: a hard onshore blow holds water in and makes a predicted low shallower and later, and a cold, dry high-pressure spell does the opposite. NOAA publishes observed levels alongside its predictions for exactly this reason. The numbers here are also the station's water, not the water two miles up a tidal creek, where the same tide arrives later and smaller. On rivers a spring freshet outweighs the tide outright.

Tide is the hour; it does not tell you which hour is worth taking. The reasoning behind the solunar windows — and what they are worth on a coast where moving water already sets the hour — is in best fishing times. The rest of the grid is catalogued on the fishing forecast hub. A printed page is also poor company in a creek at first light, and which fishing apps actually carry tide tables is a separate comparison.

The nearest stations this site carries are Sarasota, FL (1.4 ft), Venice, FL (1.56 ft), Cedar Key, FL (2.83 ft), Pensacola, FL (1.2 ft) and Galveston, TX (1.46 ft), and the full list with the station behind each one is on the tide charts hub.