Oʻahu, United States · Pacific/Honolulu

Sandy Beach

Sharp reef make-up with a close-out on a low tide and a workable shoulder on a mid.

18:00 local · 2026-10-04

66% — the read for this hour

Worth the drive66%

Swell

0.64 m

Period

8 s

Swell from

151°

Wind

7.3 m/s

Wind from

57°

Air

24°C

Worth the drive66%

Worth the drive. At Sandy Beach on this hour the read is 66%. What earns it: peel speed at 13.2 km/h. What costs it: swell power at 2.0 kW/m.

23 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, 21:00, 22:00, 23:00.

Tide window for a beachbreak: 0.8–2.2 m of water over the take-off; below 0.30 m it works across the tide matters and the reef is exposed.

Sandy Beach · 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: 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 · Sandy BeachBeachbreak — sand shifting under the take-off

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

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 eb9bf9c499e8…

Water over take-off: exposed
Break height: 0.28 m
Peel speed: 13.2 km/h
Wave power: 2.0 kW/m

Worth the drive. At Sandy Beach on this hour the read is 66%. What earns it: peel speed at 13.2 km/h. What costs it: swell power at 2.0 kW/m.

Every factor, re-weighted for this tide

Swell power2.0 kW/m · 2.0%
Peel speed13.2 km/h · 20.0%
Wind quality7.3 m/s 94° off · 10.7%
Tide window1.37 m over the take-off · 18.0%
Direction match23° off the 128° peel · 11.0%
Period cleanliness7.8 s · 4.2%

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 power2.0 kW/m · 2.0%
weight 0.220
Peel speed13.2 km/h · 20.0%
weight 0.200
Wind quality7.3 m/s 94° off · 10.7%
weight 0.200
Tide window1.37 m over the take-off · 18.0%
weight 0.180
Direction match23° off the 128° peel · 11.0%
weight 0.120
Period cleanliness7.8 s · 4.2%
weight 0.080

engine seal eb9bf9c499e8953f6f96e8e814ccad7f2b4b99639884383d6b3e64e60ff3fc0a8d863691cd638b5a9e0bcdbd99bacf94

Swell power
P = 1/16 · rho · g · Hs² · Tp = 0.628 · 0.64² · 8 = 2.0 kW/m, against a 22 kW/m "serious day" reference.
Peel speed
c = sqrt(g · depth) = sqrt(9.81 · 1.37 m) = 13.2 km/h over a 1.37 m take-off, with 0.28 m standing up. Full marks 8.5–19 km/h: slower is mush, faster than ~25 km/h is unridable.
Wind quality
Wind is 94° off at 7.3 m/s. Alignment = 1 − (1 + cos 94°)/2 = 0.53; speed envelope at 7.3 m/s = 1.00. Product 0.53.
Tide window
beachbreak works across the tide. Ideal band 0.8–2.2 m of water over the take-off; below 0.30 m the reef is exposed.
Direction match
Swell from 151°, this break peels cleanly from 128°. 23° of error: inside 12° is full marks, past 75° the swell wraps the headland and does not arrive.
Period cleanliness
Tp = 7.8 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 20:27 UTC168 hourly rows, swell and wind wave.
liveOpen-Meteo Forecast APICC BY 4.0, non-commercial attribution requiredfetched 2026-10-04 20:27 UTC168 hourly rows, wind and air.
liveNOAA CO-OPS tide predictionsU.S. Government public domainfetched 2026-10-04 20:27 UTC144 hourly predictions, MLLW datum, station 1611400 (Honolulu, Oʻahu).

Snapshot generated 2026-10-04T20:27:45.385Z. Break orientation, reef slope and take-off depth come from this project's catalogue and are labelled as estimates, not survey data.