Every surf forecast is a number in feet. This is what those feet look like standing next to you, who each size suits, and why the same wave gets called two different heights in Hawaii.
Surf is measured as the wave FACE, from trough to crest. That is how the National Weather Service publishes it, and it is the number we show on every spot card. The easiest way to hold it in your head is the body reference scale: a 3 ft wave breaks at about waist height on a surfer, a 5 ft wave is head high, and anything past that is overhead.
It matters because the jump from 3 ft to 5 ft is not a small change in a number. It is the difference between a wave you can fall off all morning and a wave with enough water moving to hold you down. The zones below are the same thresholds we use to grade every spot on the live report.
Today, on this scale
The live forecast, drawn against a person. This is the shore running biggest on the Big Island right now.
3-5 ftsouth shore
Ankle high1 ft
Knee to thigh2 ft
Waist high3 ft
Chest to shoulder4 ft
Head high5 ft
Overhead8 ft
Double overhead10+ ft
Barrels and carving, with real consequences attached.
A mellow, gentle roll with very little push behind it.
What people ride
A soft-top foamie (8 to 9 ft or more), a traditional longboard, or a high-volume funboard.
Who it is for
First-timers learning to pop up, finding their balance, riding their first open green face rather than whitewater.
Why it works
Low impact and easy to paddle into. Fall off and the wave has almost no power to hold you under, which is what makes the learning curve survivable.
1 ft - 3 ft: Absolute beginner to early intermediate
3 to 5 ft
Intermediate zone
Chest to head high
How it feels
Real pocket speed and a proper wall to turn on. Punchy drops by 5 ft.
What people ride
A performance longboard, a fish, a mid-length, or your daily-driver shortboard.
Who it is for
Surfers who can already catch and ride, working on generating speed, trimming down the line, cutbacks and steeper takeoffs.
Why it works
Enough wall and push to actually practise manoeuvres, without being punishing when you get caught inside or take a set on the head.
3 ft - 5 ft: Intermediate, edging into advanced at the top
5 ft and up
Advanced and expert zone
Overhead to double overhead
How it feels
Fast, heavy and deep. Every paddle out is work before the first wave.
What people ride
A performance shortboard, a step-up, or a gun once it is over 10 ft.
Who it is for
Experienced surfers with paddling stamina, solid wave reading, and honest breath-hold confidence during a long hold-down.
Why it works
This is where barrel sections and high-speed carving live, and it carries the matching risk: broken leashes, snapped boards, and being held under long enough to matter.
5 ft +: Advanced to expert only
If the beginner zone reads like you, the fastest way in is a lesson. Most people stand up on their first wave at Waikīkī, and that is not luck: the rollers there are slow and long, and an instructor picks the wave and times the push for you. Browse Waikīkī surf lessons on Viator
Tour links are affiliate links to Viator; we may earn a commission at no cost to you.
Quick reference
The same scale in finer steps, because the two feet between chest high and head high change the day more than any other two feet on this table.
Face height
On a person
Experience level
Energy and feel
1 to 2 ft
Ankle to knee
Absolute beginner
Mellow, gentle roll. Minimal push.
2 to 3 ft
Knee to waist
Beginner to early intermediate
Easy pop-ups, fun green faces.
3 to 4 ft
Waist to chest
Intermediate
Good pocket speed, fun walls for turns.
4 to 5 ft
Shoulder to head high
Intermediate to advanced
Punchy drops, fast sections, real push.
6 to 8 ft
Overhead and up
Advanced to expert
Heavy, fast. Deep paddling required.
10 ft and over
Double overhead
Expert
Big-wave surfing. A gun, a plan, and people watching you.
The Hawaiian scale, and why our number looks bigger
Ask someone at the beach how big it is and you may get half the number you just read on a forecast. They are not disagreeing with you. They are quoting Hawaiian feet, measuring the back of the wave the way it has been done here for generations, while forecasts measure the face. Someone who says it is three feet Hawaiian and a forecast that says six feet are describing the same wave.
6 ft face
Face height, trough to crest. What we publish, and what NWS publishes.
3 ft Hawaiian
The same wave read from the back. What you will hear called a 3 ft day.
The working rule: a 3 ft Hawaiian wave is a 6 ft face, which is head high to overhead. When you are deciding whether a day suits you, use face height. We never publish a Hawaiian-scale number, because halving a safety-relevant height to sound local would under-report the danger.
How big is too big, by Big Island shore
The body scale is universal. The line where a coast becomes dangerous is not. The National Weather Service sets its high surf thresholds per shore, and on this island the leeward Kona coast crosses into advisory territory at a height the north shore handles as an ordinary day. That is why a spot card can read Not today at 8 ft on one coast and Experienced at 12 ft on another.
Shore
Advisory at
Warning at
north shore
15 ft
25 ft
east shore
10 ft
15 ft
south shore
10 ft
15 ft
west shore
8 ft
12 ft
Advisory means the surf is dangerous to anyone not experienced in it, and it is where we stop showing a break as somewhere to learn. Warning means stay out of the water and watch from well back. Both are National Weather Service thresholds for the Big Island specifically; the other islands use different numbers.
Where each number comes from
Face height has an issuing authority and we quote it. The National Weather Service Honolulu states it plainly: “All surf height observations and forecasts are for the full face surf height, from the trough to the crest of the wave.” Every height on this site, and every threshold in the table beside this one, comes from that office.
The Hawaiian scale does not have one, and that is the honest answer to a question people search for. No agency, standards body or scientific reference defines it; its origins are genuinely obscure, and the halving is a convention passed along by surfers, lifeguards and local surf reports rather than a published rule. That is precisely why we do not print it. A number nobody issues is a number nobody can be held to, and this one runs in the direction that under-reports danger.
There is no single useful answer, and any site that gives you one number is averaging away the thing that decides your day. Wave height here is a property of a SHORE in a SEASON, not of the state. In July a north-facing beach can sit at 1 to 2 ft while a south-facing one a few miles away is over its advisory line; in January the two swap.
That is physics rather than local lore: north-facing coasts work in the northern winter, south-facing in the northern summer, west catches both, and east has trade swell most of the year. So the honest version of the question is which shore, on which day, and the live report answers it with today’s actual numbers.
What can be said generally is that an advisory is by definition the exception. Most days most shores run well under the thresholds in the table above, which is why those thresholds are worth knowing: they are the line where an ordinary day becomes one to watch from the sand.
Check the shore, not the island. Which way a coast faces decides what swell reaches it. A 10 ft south swell can be running while the north shore sits at 2 ft.
Take the top of the range, not the middle. A forecast of 4 to 6 ft means sets of 6 ft, and the set wave is the one you have to deal with.
Period matters as much as height. A 4 ft swell at 16 seconds carries far more water than 4 ft at 8 seconds. The buoy readout on the live report shows both.
Half the day can be a different day. Morning is usually cleanest before the trades fill in, and our spot cards show whichever half of the day is bigger.
The forecast is a heads-up, not a green light. Conditions at the beach win, and the lifeguard there knows the rip you cannot see in any number.
Surf heights and high surf thresholds: National Weather Service Honolulu, which publishes full face height, trough to crest. Body reference scale: standard surf industry usage, also face height, so no conversion is applied anywhere on this site. The Hawaiian scale has no issuing authority and we do not publish it. Independent project, affiliated with none of the above.