Midway Atoll, United States · Pacific/Midway
North Shore
Genuinely remote, and the only spot in this list where the tide station is the break.
23:00 local · 2026-10-04
72% — the read for this hour
Swell
1.90 m
Period
9 s
Swell from
183°
Wind
9.3 m/s
Wind from
110°
Air
26°C
Get in the water. At North Shore on this hour the read is 72%. What earns it: swell power at 20.1 kW/m. What costs it: direction match at 151° 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.
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.
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
- Water over take-off
- exposed
- Break height
- 0.98 m
- Peel speed
- 15.0 km/h
- Wave power
- 20.1 kW/m
Get in the water. At North Shore on this hour the read is 72%. What earns it: swell power at 20.1 kW/m. What costs it: direction match at 151° off the 32° peel.
Every factor, re-weighted for this tide
- Swell power20.1 kW/m · 20.1%
- Peel speed15.0 km/h · 20.0%
- Wind quality9.3 m/s 73° off · 6.3%
- Tide window1.77 m over the take-off · 18.0%
- Direction match151° off the 32° peel · 0.0%
- Period cleanliness8.8 s · 7.3%
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 power20.1 kW/m · 20.1%
weight 0.220
- Peel speed15.0 km/h · 20.0%
weight 0.200
- Wind quality9.3 m/s 73° off · 6.3%
weight 0.200
- Tide window1.77 m over the take-off · 18.0%
weight 0.180
- Direction match151° off the 32° peel · 0.0%
weight 0.120
- Period cleanliness8.8 s · 7.3%
weight 0.080
engine seal ee544dc11c8045be6cf868023eab1af7b75ae676c5c301a8cd18b5e9de044f4b765c14cde5527b25aed9854701a19f54
Swell power
P = 1/16 · rho · g · Hs² · Tp = 0.628 · 1.90² · 9 = 20.1 kW/m, against a 22 kW/m "serious day" reference.
Peel speed
c = sqrt(g · depth) = sqrt(9.81 · 1.77 m) = 15.0 km/h over a 1.77 m take-off, with 0.98 m standing up. Full marks 8.5–19 km/h: slower is mush, faster than ~25 km/h is unridable.
Wind quality
Wind is 73° off at 9.3 m/s. Alignment = 1 − (1 + cos 73°)/2 = 0.35; speed envelope at 9.3 m/s = 0.88. Product 0.31.
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 183°, this break peels cleanly from 32°. 151° of error: inside 12° is full marks, past 75° the swell wraps the headland and does not arrive.
Period cleanliness
Tp = 8.8 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 20:32 UTC168 hourly rows, swell and wind wave.
- liveOpen-Meteo Forecast APICC BY 4.0, non-commercial attribution requiredfetched 2026-10-04 20:32 UTC168 hourly rows, wind and air.
- liveNOAA CO-OPS tide predictionsU.S. Government public domainfetched 2026-10-04 20:32 UTC144 hourly predictions, MLLW datum, station 1612340 (Midway Atoll).
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.