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Swellread

Midway Atoll, United States · Pacific/Midway

North Shore

Genuinely remote, and the only spot in this list where the tide station is the break.

00:00 local · 2026-10-04

64% — the read for this hour

Worth the drive64%

Swell

1.62 m

Period

10 s

Swell from

126°

Wind

13.3 m/s

Wind from

71°

Air

27°C

Worth the drive64%

Worth the drive. At North Shore on this hour the read is 64%. What earns it: peel speed at 14.6 km/h. What costs it: direction match at 94° off the 32° peel.

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

Tide window for a reef pass: 0.9–2 m of water over the take-off; below 0.60 m it needs the pass covered matters and the reef is exposed.

North Shore · 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
Midway Atoll
Datum
MLLW
Range
0.63 m
Mean
0.29 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 · North ShoreReef pass — a channel cut through the outer barrier reef
take-off0m3m6m9m12m15moffshoreinshore · tanβ 0.09
0.18 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 64%seal 237bc0c5b740…
Water over take-off
exposed
Break height
0.83 m
Peel speed
14.6 km/h
Wave power
16.8 kW/m

Worth the drive. At North Shore on this hour the read is 64%. What earns it: peel speed at 14.6 km/h. What costs it: direction match at 94° off the 32° peel.

Every factor, re-weighted for this tide

  • Swell power16.8 kW/m · 16.8%
  • Peel speed14.6 km/h · 20.0%
  • Wind quality13.3 m/s 55° off · 1.1%
  • Tide window1.68 m over the take-off · 18.0%
  • Direction match94° off the 32° peel · 0.0%
  • Period cleanliness10.2 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 power16.8 kW/m · 16.8%

    weight 0.220

  • Peel speed14.6 km/h · 20.0%

    weight 0.200

  • Wind quality13.3 m/s 55° off · 1.1%

    weight 0.200

  • Tide window1.68 m over the take-off · 18.0%

    weight 0.180

  • Direction match94° off the 32° peel · 0.0%

    weight 0.120

  • Period cleanliness10.2 s · 8.0%

    weight 0.080

engine seal 237bc0c5b7400f14c8e08ec3dde67ab72548687ef71a6cc9a066ca516c71393cd667ba76a4ba39df073f84231d9901f4

  • Swell power

    P = 1/16 · rho · g · Hs² · Tp = 0.628 · 1.62² · 10 = 16.8 kW/m, against a 22 kW/m "serious day" reference.

  • Peel speed

    c = sqrt(g · depth) = sqrt(9.81 · 1.68 m) = 14.6 km/h over a 1.68 m take-off, with 0.83 m standing up. Full marks 8.5–19 km/h: slower is mush, faster than ~25 km/h is unridable.

  • Wind quality

    Wind is 55° off at 13.3 m/s. Alignment = 1 − (1 + cos 55°)/2 = 0.21; speed envelope at 13.3 m/s = 0.25. Product 0.05.

  • Tide window

    reef pass needs the pass covered. Ideal band 0.9–2 m of water over the take-off; below 0.60 m the reef is exposed.

  • Direction match

    Swell from 126°, this break peels cleanly from 32°. 94° of error: inside 12° is full marks, past 75° the swell wraps the headland and does not arrive.

  • Period cleanliness

    Tp = 10.2 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 2026-10-04T20:32:06.880Z. Break orientation, reef slope and take-off depth come from this project's catalogue and are labelled as estimates, not survey data.

North Shore, Midway Atoll · Swellread