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.

04:00 local · 2026-10-04

68% — the read for this hour

Worth the drive68%

Swell

0.78 m

Period

9 s

Swell from

187°

Wind

6.2 m/s

Wind from

57°

Air

26°C

Worth the drive68%

Worth the drive. At Sandy Beach on this hour the read is 68%. What earns it: peel speed at 13.0 km/h. What costs it: direction match at 59° off the 128° peel.

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

0.13 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 68%seal c17f2edb3673…

Water over take-off: exposed
Break height: 0.35 m
Peel speed: 13.0 km/h
Wave power: 3.5 kW/m

Worth the drive. At Sandy Beach on this hour the read is 68%. What earns it: peel speed at 13.0 km/h. What costs it: direction match at 59° off the 128° peel.

Every factor, re-weighted for this tide

Swell power3.5 kW/m · 3.5%
Peel speed13.0 km/h · 20.0%
Wind quality6.2 m/s 130° off · 16.4%
Tide window1.33 m over the take-off · 18.0%
Direction match59° off the 128° peel · 1.9%
Period cleanliness9.3 s · 7.9%

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 power3.5 kW/m · 3.5%
weight 0.220
Peel speed13.0 km/h · 20.0%
weight 0.200
Wind quality6.2 m/s 130° off · 16.4%
weight 0.200
Tide window1.33 m over the take-off · 18.0%
weight 0.180
Direction match59° off the 128° peel · 1.9%
weight 0.120
Period cleanliness9.3 s · 7.9%
weight 0.080

engine seal c17f2edb3673730b353da03036241e2ce72ba26c42d0b94dfc625633e2958eb49a59514eb241fd5358a4226e5a376b83

Swell power
P = 1/16 · rho · g · Hs² · Tp = 0.628 · 0.78² · 9 = 3.5 kW/m, against a 22 kW/m "serious day" reference.
Peel speed
c = sqrt(g · depth) = sqrt(9.81 · 1.33 m) = 13.0 km/h over a 1.33 m take-off, with 0.35 m standing up. Full marks 8.5–19 km/h: slower is mush, faster than ~25 km/h is unridable.
Wind quality
Wind is 130° off at 6.2 m/s. Alignment = 1 − (1 + cos 130°)/2 = 0.82; speed envelope at 6.2 m/s = 1.00. Product 0.82.
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 187°, this break peels cleanly from 128°. 59° of error: inside 12° is full marks, past 75° the swell wraps the headland and does not arrive.
Period cleanliness
Tp = 9.3 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 2026-10-04T20:27:02.649Z. Break orientation, reef slope and take-off depth come from this project's catalogue and are labelled as estimates, not survey data.