How to Read a Tide Chart

Tide charts look simple once you know what the curve is actually showing. Here's a plain-language walkthrough, plus how to use the chart inside Simple Tides.

What a tide chart shows

A tide chart plots water height over time at a specific station. The wavy line rises toward each high tide and falls toward each low tide. The steepest part of the curve is when the water is moving fastest; the flatter stretches near the top and bottom are when the tide is closest to turning.

High tide, low tide, and tide range

High tide is the point where water reaches its highest level in that cycle; low tide is the lowest point. The vertical distance between a high and the low that follows it is the tide range. A larger range generally means faster-moving water in between, which matters for boating, wading, and fishing.

Types of tides

Most of the U.S. Atlantic and Gulf coasts see semidiurnal tides: two highs and two lows of roughly similar size each day. Much of the West Coast sees a mixed semidiurnal pattern, where the two highs (and two lows) differ noticeably in height. Some places, including parts of the Gulf of Mexico, see a diurnal pattern with only one high and one low per day. The station you're looking at determines which pattern applies.

Reading the chart in Simple Tides

When you select a station, Simple Tides draws a short-range chart from now through the next forecast points, alongside a plain-text timeline listing each upcoming high and low with its time. Use the chart to see the shape of the day at a glance, and the timeline when you need an exact time to plan around.

Using tide timing to plan a trip

Slack tide — the brief period around high or low when water movement is slowest — is often easier for wading, small boats, and certain kinds of fishing. Faster-moving water mid-tide can mean stronger currents but also more active feeding, which is part of what Simple Tides factors into its Smart Bite Score.

Quick glossary

Next: learn about how NOAA tide stations work or see how tide movement feeds into the Smart Bite Score.