Tide, beach, wave and fishing guides

• Tides

  What causes tides, and why are there two a day?

  Tides are the rise and fall of the sea driven by the moon and sun. See why most coasts get two high tides a day and why they come about 50 minutes later.

  Read the guide
• Tides

  How to read a tide chart: high tide, low tide and heights

  What the times, heights and minus signs on a tide chart mean, with a worked Charleston example and the rule of twelfths to estimate the water hour by hour.

  Read the guide
• Fishing

  Fishing the tides: from shore and from a boat

  When to fish the incoming tide, the outgoing tide or slack water, from the beach, a jetty or a boat, with a worked example for planning a morning trip.

  Read the guide

Why the sea rises and falls, how to read a tide chart, and what spring tides and tide heights really mean.

• What causes tides, and why are there two a day?

  Tides are the rise and fall of the sea driven by the moon and sun. See why most coasts get two high tides a day and why they come about 50 minutes later.

  7 min read

• How to read a tide chart: high tide, low tide and heights

  What the times, heights and minus signs on a tide chart mean, with a worked Charleston example and the rule of twelfths to estimate the water hour by hour.

  6 min read

• Spring and neap tides, and the tide coefficient

  Why tides run bigger around every new and full moon and smaller at the quarter moons, what king tides are, and how Europe's tide coefficient rates them.

  5 min read

• Types of tides: semidiurnal, diurnal and mixed

  Some coasts get two even tides a day, some get two uneven ones, and some get just one. What semidiurnal, mixed and diurnal tides are, and why they happen.

  6 min read

• Chart datum and MLLW: where tide heights are measured from

  What chart datum and MLLW are, why US tide charts show minus tides, and how to add tide height to charted depth to know how much water you really have.

  5 min read

• Why some seas have almost no tide

  The Mediterranean, the Baltic and the Great Lakes barely have tides, and Gulf of Mexico tides are small and once a day. Here's why, and what moves the water.

  6 min read

• The biggest tides in the world: where and why

  The biggest tides in the world reach about 53 feet in Canada's Bay of Fundy. Where else the sea rises highest, from Alaska to Maine and France, and why.

  9 min read

• The rule of twelfths: how to calculate tide height

  The rule of twelfths lets you calculate tide height at any time: 1, 2, 3, 3, 2, 1 twelfths. A worked Boston example, bar crossings and when it fails.

  9 min read

• Storm surge and storm tide: when storms raise the sea

  Storm surge is the rise in sea level a storm causes on top of the tide. How wind and low pressure drive it, storm surge vs. storm tide, and why timing matters.

  9 min read

• Why the tide is higher or lower than predicted

  Why is the tide higher than predicted? Air pressure, wind, waves, rivers and seiches move the water, and so do station, time zone and datum mix-ups.

  9 min read

• Supermoons and king tides: how much higher the tide really gets

  Supermoon tides and king tides: what a supermoon is, how much bigger it looks, how much higher the tide really gets, and the supermoons of 2027.

  9 min read

When to fish based on the tide, the solunar periods, the moon phase and the light at dawn and dusk.

• Solunar theory: major and minor fishing periods

  What solunar theory is, how the moon sets the major and minor periods, and how to use them for fishing alongside the tide, the light and the weather.

  6 min read

• Fishing the tides: from shore and from a boat

  When to fish the incoming tide, the outgoing tide or slack water, from the beach, a jetty or a boat, with a worked example for planning a morning trip.

  6 min read

• Moon phases and fishing: what really matters

  How the moon affects fishing through the tides, night light and solunar periods, which phases anglers favor for different fish, and what is just folklore.

  6 min read

• Dawn, dusk and golden hour: the best light for fishing

  What civil, nautical and astronomical twilight and golden hour mean, how long they last across the US, and why dawn and dusk are prime times to fish.

  5 min read

• Barometric pressure and fishing: what the science says

  Barometric pressure and fishing: what studies actually show, the best barometric pressure for fishing according to anglers, and what matters more.

  9 min read

How the water moves, what beach flags mean, how to escape a rip current and what to do about jellyfish or storms.

• Tidal currents: flood, ebb and slack water

  When the tide rises and falls, the water also moves sideways. What flood, ebb and slack water mean, when currents run hardest, and where to be careful.

  5 min read

• Tide safety: wading, clamming and not getting cut off

  How to avoid getting cut off by the tide when you wade, dig clams, fish the flats or explore tide pools, and why the lowest minus tides need the most care.

  6 min read

• Rip currents: how to spot one and how to escape

  Rip current safety: how to spot a rip from the beach, how to escape one if it pulls you out, and how to help someone else without becoming a second victim.

  8 min read

• Beach warning flags: what each color means

  Beach flag colors and meanings: green, yellow, red, double red and purple flags in the US, plus the red-and-yellow flags used in the UK and Australia.

  8 min read

• Jellyfish at the beach: what to do if you get stung

  Jellyfish at the beach: what to do if you get stung, what never to do, when vinegar helps and when it hurts, and when a sting means calling 911.

  9 min read

• Lightning safety at the beach: what to do when you hear thunder

  Lightning at the beach: why sand and water are so exposed, how far lightning can strike from a storm, where to shelter and why you wait 30 minutes.

  8 min read

How to read a surf forecast, what swell period means, the Beaufort scale, which wetsuit to wear and when to dive with the tide.

• How to read a surf forecast: swell, period, wind and tide

  How to read a surf forecast: significant wave height, swell period and direction, offshore vs onshore wind and tide, with a sample surf report explained.

  9 min read

• Swell period explained: why seconds matter as much as feet

  Swell period explained: why waves with more seconds between crests carry more energy and break bigger, what period is good for surfing and typical U.S. values.

  8 min read

• The Beaufort scale: wind force from 0 to 12

  Beaufort scale chart from force 0 to 12 in knots, mph and m/s, with each force's name, sea state and wave height, plus what force 7 means.

  8 min read

• Knots to mph: what a knot is and how to convert it

  Knots to mph: a knot is one nautical mile per hour, about 1.151 mph or exactly 1.852 km/h. Chart from 1 to 60 knots, mental math tricks and the name's origin.

  8 min read

• Diving and tides: slack water and the best time to dive

  Best tide for diving and snorkeling: why slack water matters, why it often isn't at high tide, when visibility is best and how to plan the time of your dive.

  9 min read

• Water temperature and wetsuits: what thickness do you need?

  Wetsuit temperature chart in °F and °C: what thickness you need (3/2, 4/3, 5/4), how surfing, diving and swimming differ, and how cold water shock works.

  9 min read

• Coastal places

  Tides, sun, moon and solunar times for every town, beach and harbor.

• Sunrise and sunset

  Sunrise, sunset, twilight and golden hour for any place.

• Moon calendar

  Every moon phase of the year, plus eclipses and supermoons.