Midway Atoll, United States · Pacific/Midway

North Shore

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

11:00 local · 2026-10-04

48% — the read for this hour

Marginal48%

Swell

2.66 m

Period

9 s

Swell from

135°

Wind

11.7 m/s

Wind from

96°

Air

26°C

Marginal48%

Marginal — one good hour at most. Gated down from 68%: Swell at 2.66 m — big enough to hold you under on a bad take-off.

warnSwell at 2.66 m — big enough to hold you under on a bad take-off.

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

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

Drag the tide — what-if only, nothing stored is changed

0.65 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

Marginal 48%seal 116f32252eb7…

Water over take-off: exposed
Break height: 1.37 m
Peel speed: 16.5 km/h
Wave power: 40.2 kW/m

Marginal — one good hour at most. Gated down from 68%: Swell at 2.66 m — big enough to hold you under on a bad take-off.

Every factor, re-weighted for this tide

Swell power40.2 kW/m · 22.0%
Peel speed16.5 km/h · 20.0%
Wind quality11.7 m/s 39° off · 1.1%
Tide window2.15 m over the take-off · 17.7%
Direction match103° off the 32° peel · 0.0%
Period cleanliness9.1 s · 7.6%

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 power40.2 kW/m · 22.0%
weight 0.220
Peel speed16.5 km/h · 20.0%
weight 0.200
Wind quality11.7 m/s 39° off · 1.1%
weight 0.200
Tide window2.15 m over the take-off · 17.7%
weight 0.180
Direction match103° off the 32° peel · 0.0%
weight 0.120
Period cleanliness9.1 s · 7.6%
weight 0.080

engine seal 116f32252eb7cbad86b170c21360b4c1e54ca3b4be636a22959582aa5bc8e28032e148b3b82222daab8142b8e1502ad6

Swell power
P = 1/16 · rho · g · Hs² · Tp = 0.628 · 2.66² · 9 = 40.2 kW/m, against a 22 kW/m "serious day" reference.
Peel speed
c = sqrt(g · depth) = sqrt(9.81 · 2.15 m) = 16.5 km/h over a 2.15 m take-off, with 1.37 m standing up. Full marks 8.5–19 km/h: slower is mush, faster than ~25 km/h is unridable.
Wind quality
Wind is 39° off at 11.7 m/s. Alignment = 1 − (1 + cos 39°)/2 = 0.11; speed envelope at 11.7 m/s = 0.51. Product 0.06.
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 135°, this break peels cleanly from 32°. 103° of error: inside 12° is full marks, past 75° the swell wraps the headland and does not arrive.
Period cleanliness
Tp = 9.1 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

liveOpen-Meteo Marine APICC BY 4.0, non-commercial attribution requiredfetched 2026-10-04 21:16 UTC168 hourly rows, swell and wind wave.
liveOpen-Meteo Forecast APICC BY 4.0, non-commercial attribution requiredfetched 2026-10-04 21:16 UTC168 hourly rows, wind and air.
liveNOAA CO-OPS tide predictionsU.S. Government public domainfetched 2026-10-04 21:16 UTC144 hourly predictions, MLLW datum, station 1612340 (Midway Atoll).

Snapshot generated 2026-10-04T21:16:07.132Z. Break orientation, reef slope and take-off depth come from this project's catalogue and are labelled as estimates, not survey data.