Bali, Indonesia · Asia/Makassar

Uluwatu

A long shallow left with almost no take-off options. Low tide is a genuine hazard, so the reef-exposed gate matters more than the score.

Part of this page is live and part is not.

See the source list at the bottom for exactly which feed answered.

04:00 local · 2026-10-05

72% — the read for this hour

Get in the water72%

Swell

1.70 m

Period

10 s

Swell from

201°

Wind

0.9 m/s

Wind from

58°

Air

24°C

Get in the water72%

Get in the water. At Uluwatu on this hour the read is 72%. What earns it: swell power at 17.6 kW/m. What costs it: wind quality at 0.9 m/s 143° off. Not scored, because no real data exists: Peel speed, Tide window.

24 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, 20:00, 21:00, 22:00, 23:00.

Tide window for a reef: 0.6–1.4 m of water over the take-off; below 0.40 m it wants the reef just covered matters and the reef is exposed.

Uluwatu · 24 hours, local timemixed data

score tide (dashed, MLLW) swell height nowno tide station in range

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

No tide station in range, so no tide value is shown anywhere in this app.

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 · UluwatuFringing reef — the swell stands up on a shallow shelf

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

0.70 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 72%seal a92a556705ce…

Water over take-off: exposed
Break height: —
Peel speed: —
Wave power: 17.6 kW/m

Every factor, re-weighted for this tide

Swell power17.6 kW/m · 28.4%
Peel speedneeds a tide height
Wind quality0.9 m/s 143° off · 12.8%
Tide windowno verified tide in range
Direction match21° off the 222° peel · 18.3%
Period cleanliness9.7 s · 12.9%

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 power17.6 kW/m · 28.4%
weight 0.355
Peel speedneeds a tide height
weight 0.000 — dropped, not guessed
Wind quality0.9 m/s 143° off · 12.8%
weight 0.323
Tide windowno verified tide in range
weight 0.000 — dropped, not guessed
Direction match21° off the 222° peel · 18.3%
weight 0.194
Period cleanliness9.7 s · 12.9%
weight 0.129

engine seal a92a556705cec641bf622bf5ba7edd6e7cd2252e0ebe6ae4a0b2da10ad65688ab7275c7ab6c21106377e6ac4464e9680

Swell power
P = 1/16 · rho · g · Hs² · Tp = 0.628 · 1.70² · 10 = 17.6 kW/m, against a 22 kW/m "serious day" reference.
Peel speednot scored
Peel speed is shallow-water celerity, so without a verified tide height there is no depth to take the square root of. This factor is dropped rather than guessed.
Wind quality
Wind is 143° off at 0.9 m/s. Alignment = 1 − (1 + cos 143°)/2 = 0.90; speed envelope at 0.9 m/s = 0.44. Product 0.40.
Tide windownot scored
This break has no NOAA CO-OPS tide station in range, so the tide window cannot be scored. Weights are renormalised without it instead of substituting a guess.
Direction match
Swell from 201°, this break peels cleanly from 222°. 21° of error: inside 12° is full marks, past 75° the swell wraps the headland and does not arrive.
Period cleanliness
Tp = 9.7 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 20:29 UTC168 hourly rows, swell and wind wave.
liveOpen-Meteo Forecast APICC BY 4.0, non-commercial attribution requiredfetched 2026-10-04 20:29 UTC168 hourly rows, wind and air.
fallbackNOAA CO-OPS tide predictionsU.S. Government public domainfetched 2026-10-04 20:29 UTCNo NOAA CO-OPS station is in range for this break, so no tide value is available and the tide factor is dropped.

Snapshot generated 2026-10-04T20:29:19.760Z. Break orientation, reef slope and take-off depth come from this project's catalogue and are labelled as estimates, not survey data.