Midway Atoll, United States · Pacific/Midway

North Shore

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

19:00 local · 2026-10-04

71% — the read for this hour

Get in the water71%

Swell

2.34 m

Period

9 s

Swell from

168°

Wind

9.8 m/s

Wind from

111°

Air

27°C

Get in the water71%

Get in the water. At North Shore on this hour the read is 71%. What earns it: swell power at 29.8 kW/m. What costs it: direction match at 136° 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

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

0.09 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

Get in the water 71%seal a54169b9800c…

Water over take-off: exposed
Break height: 1.20 m
Peel speed: 14.2 km/h
Wave power: 29.8 kW/m

Get in the water. At North Shore on this hour the read is 71%. What earns it: swell power at 29.8 kW/m. What costs it: direction match at 136° off the 32° peel.

Every factor, re-weighted for this tide

Swell power29.8 kW/m · 22.0%
Peel speed14.2 km/h · 20.0%
Wind quality9.8 m/s 57° off · 3.7%
Tide window1.59 m over the take-off · 18.0%
Direction match136° off the 32° peel · 0.0%
Period cleanliness8.7 s · 6.8%

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 power29.8 kW/m · 22.0%
weight 0.220
Peel speed14.2 km/h · 20.0%
weight 0.200
Wind quality9.8 m/s 57° off · 3.7%
weight 0.200
Tide window1.59 m over the take-off · 18.0%
weight 0.180
Direction match136° off the 32° peel · 0.0%
weight 0.120
Period cleanliness8.7 s · 6.8%
weight 0.080

engine seal a54169b9800cfaaba3466d4d4a6289db511243799ee1db44f300f0b4b1f0531de5e110cdf8ae08746507f41468bc87e7

Swell power
P = 1/16 · rho · g · Hs² · Tp = 0.628 · 2.34² · 9 = 29.8 kW/m, against a 22 kW/m "serious day" reference.
Peel speed
c = sqrt(g · depth) = sqrt(9.81 · 1.59 m) = 14.2 km/h over a 1.59 m take-off, with 1.20 m standing up. Full marks 8.5–19 km/h: slower is mush, faster than ~25 km/h is unridable.
Wind quality
Wind is 57° off at 9.8 m/s. Alignment = 1 − (1 + cos 57°)/2 = 0.23; speed envelope at 9.8 m/s = 0.81. Product 0.18.
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 168°, this break peels cleanly from 32°. 136° of error: inside 12° is full marks, past 75° the swell wraps the headland and does not arrive.
Period cleanliness
Tp = 8.7 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.