Tide Chart Viewer
Live 7-day tide predictions for thousands of US NOAA stations, with a nearest-station finder and tide curve — and what predictions cannot include.
Pick how to find your tide station — the list covers 3,499 NOAA prediction stations on US coasts.
Tide predictions
Live NOAA CO-OPS predictions (station local time, feet above MLLW). The curve between highs and lows is cosine-interpolated — the standard tide shape — while the marked extremes are NOAA's exact predictions. Predictions ignore weather: storm surge and strong winds can move real water by feet. Never use this page for navigation safety.
The tide keeps lunar time, not solar time
The Earth turns once in 24 hours, but the Moon has moved on in that time, so bringing the same point back under it takes 24.84 hours. Two high tides per lunar day gives a period of 12 hours 25 minutes — and a drift of 50 minutes against the clock, every day.
| If high tide is 06:00 today | It arrives at | Later by |
|---|---|---|
| today | 06:00 | — |
| tomorrow | 06:50 | 0.8 h |
| 2 days on | 07:41 | 1.7 h |
| 3 days on | 08:31 | 2.5 h |
| 7 days on | 11:53 | 5.9 h |
| 14 days on | 17:47 | 11.8 h |
A week's drift is 5.89 hours, which is 19 minutes short of half a cycle — close enough that this morning's high tide is next week's morning low, and far enough that it never quite settles into a weekly rhythm. A week holds 13.53 tides rather than the 14 you would guess from two a day. Which is why the table cannot be replaced by remembering what happened last weekend.
Three cycles, none of them a multiple of another
Working 50.47 minutes a day through a 24-hour clock takes 28.53 days. The Moon returns to the same phase every 29.53. Those differ by 1.00 — almost exactly one day, because the tide has to make up a whole extra cycle against the clock over the same period. On top of that, the size of the tide depends on whether the Sun and Moon pull together, which happens at new and full moon. So spring tides come every 14.77 days, about 24.7 times a year — not the 24 that twice-a-month would give.
Three cycles then: a 12h25m period, a 28.5-day return to the same clock time, and a 14.77-day spring-to-neap swing. None is a whole multiple of another, so the pattern never repeats exactly. That is why real tide prediction is done with harmonic constituents fitted to each station rather than with arithmetic, and why the chart above is fetched rather than calculated. A station's local geometry matters as much as the astronomy: the same Moon produces a half-metre range in one bay and a ten-metre range in the next one along.
How to use
- Find your nearest station.
- Read the high and low water times and heights.
- Check the datum the heights are measured from.
- Allow for weather, which predictions do not include.
Frequently asked questions
What causes tides?
The gravitational pull of the Moon and, to a lesser extent, the Sun, combined with the Earth's rotation. The Moon dominates because it is far closer, despite the Sun being vastly more massive — tidal force falls off with the cube of distance rather than the square.
Why are there two high tides a day in most places?
Because there is a tidal bulge on both the near and far sides of the Earth. The near bulge is pulled toward the Moon; the far one exists because the Earth itself is pulled away from the water on the opposite side. Some locations have only one daily cycle due to local basin geometry.
What are spring and neap tides?
Spring tides are the largest, occurring when the Sun and Moon align at new and full moon so their effects add. Neap tides are the smallest, at the quarter moons, when the two pull at right angles. Spring has nothing to do with the season — it means to leap up.
Why does the actual water level differ from the prediction?
Because predictions are astronomical only. Wind, barometric pressure, river discharge and storm surge can raise or lower the real level substantially — a strong onshore blow with low pressure can add a great deal, which is what makes coastal flooding possible on an ordinary predicted tide.
What is a tidal datum?
The reference level heights are measured from, commonly mean lower low water in the United States. It matters because a predicted height of two feet means two feet above that datum, not two feet of water — which is the distinction that runs boats aground.
Can I navigate from these predictions?
Not on their own. Official tide tables, current charts and up-to-date nautical charts are what navigation requires, and this is a convenience view of predicted data. Currents in particular are a separate prediction from heights, and they do not turn at high and low water.
🌐 This tool looks up results using NOAA CO-OPS tide API (station list + predictions); optional browser geolocation. The word you enter is sent to that service to fetch results; nothing is stored by this site.