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Swellread

Oʻahu, United States · Pacific/Honolulu

Waikiki

Long, slow, shallow. Peel speed is the whole game here, and peel speed is depth, and depth is tide.

05:00 local · 2026-10-04

66% — the read for this hour

Worth the drive66%

Swell

0.74 m

Period

10 s

Swell from

187°

Wind

3.9 m/s

Wind from

53°

Air

25°C

Worth the drive66%

Worth the drive. At Waikiki on this hour the read is 66%. What earns it: peel speed at 11.9 km/h. What costs it: direction match at 75° off the 112° peel.

24 hours worth driving for today: 00:00, 01:00, 02:00, 03:00, 04:00, 05:00, 06:00, 07:00, 08:00, 09:00, 10:00, 11:00, 12:00, 13:00, 14:00, 15:00, 16:00, 17:00, 18:00, 19:00, 20:00, 21:00, 22:00, 23:00.

Tide window for a reef: 0.6–1.4 m of water over the take-off; below 0.40 m it wants the reef just covered matters and the reef is exposed.

Waikiki · 24 hours, local timelive data
00:0003:0006:0009:0012:0015:0018:0021:00
score tide (dashed, MLLW) swell height now

Dashed line is the tide above MLLW, solid line is the swell height. Column height is the engine score for that hour. Faded columns are gated. The hour you select is in the URL, so this page is shareable as-is.

Tide station

Station
Honolulu, Oʻahu
Datum
MLLW
Range
0.58 m
Mean
0.30 m

Signature interaction

Drag the tide and watch the reef change its mind

The cross-section is drawn from the break's own reef slope. Every change re-runs the shared engine on the server and returns a fresh seal — this control cannot work without the API.

Seabed cross-section · WaikikiFringing reef — the swell stands up on a shallow shelf
take-off0m3m6m9m12m15moffshoreinshore · tanβ 0.06
0.17 m

The dashed arrow is the peel, at c = √(g·depth). More water over the take-off means a faster peel, which is why the same swell behaves differently at low and mid tide.

Re-solved by swellread-engine/2026.10.1

Worth the drive 66%seal f70016554c56…
Water over take-off
exposed
Break height
0.34 m
Peel speed
11.9 km/h
Wave power
3.4 kW/m

Worth the drive. At Waikiki on this hour the read is 66%. What earns it: peel speed at 11.9 km/h. What costs it: direction match at 75° off the 112° peel.

Every factor, re-weighted for this tide

  • Swell power3.4 kW/m · 3.4%
  • Peel speed11.9 km/h · 20.0%
  • Wind quality3.9 m/s 134° off · 16.9%
  • Tide window1.12 m over the take-off · 18.0%
  • Direction match75° off the 112° peel · 0.0%
  • Period cleanliness9.9 s · 8.0%

Show your working

Every factor, its weight, and the arithmetic behind it

Weights are renormalised over the factors that have real data behind them. A factor with no data is dropped and said so, never quietly scored at zero.

  • Swell power3.4 kW/m · 3.4%

    weight 0.220

  • Peel speed11.9 km/h · 20.0%

    weight 0.200

  • Wind quality3.9 m/s 134° off · 16.9%

    weight 0.200

  • Tide window1.12 m over the take-off · 18.0%

    weight 0.180

  • Direction match75° off the 112° peel · 0.0%

    weight 0.120

  • Period cleanliness9.9 s · 8.0%

    weight 0.080

engine seal f70016554c5626d771db94032d81cd4de057bf0262867f69c7c4ad28d042286ac65104bb6ea73bffd1a8b17be1128469

  • Swell power

    P = 1/16 · rho · g · Hs² · Tp = 0.628 · 0.74² · 10 = 3.4 kW/m, against a 22 kW/m "serious day" reference.

  • Peel speed

    c = sqrt(g · depth) = sqrt(9.81 · 1.12 m) = 11.9 km/h over a 1.12 m take-off, with 0.34 m standing up. Full marks 8.5–19 km/h: slower is mush, faster than ~25 km/h is unridable.

  • Wind quality

    Wind is 134° off at 3.9 m/s. Alignment = 1 − (1 + cos 134°)/2 = 0.85; speed envelope at 3.9 m/s = 1.00. Product 0.85.

  • Tide window

    reef wants the reef just covered. Ideal band 0.6–1.4 m of water over the take-off; below 0.40 m the reef is exposed.

  • Direction match

    Swell from 187°, this break peels cleanly from 112°. 75° of error: inside 12° is full marks, past 75° the swell wraps the headland and does not arrive.

  • Period cleanliness

    Tp = 9.9 s. Energy organises between 6 s and 9.5 s; beyond 14 s the swell stands up steeper than a shallow reef can hold, so the score is eased off by up to 35%.

Provenance

Every number above came from one of these

Snapshot generated 2026-10-04T20:29:17.757Z. Break orientation, reef slope and take-off depth come from this project's catalogue and are labelled as estimates, not survey data.

Waikiki, Oʻahu · Swellread