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Swellread

Tutuila, American Samoa · Pacific/Pago_Pago

Pago Pago

The harbour mouth stands up out of the barrier reef and peels hard left on a big south pulse. It is the reason this app exists: the numbers that make it work arrive days before anyone can see them.

22:00 local · 2026-10-04

68% — the read for this hour

Worth the drive68%

Swell

1.32 m

Period

8 s

Swell from

180°

Wind

6.9 m/s

Wind from

106°

Air

27°C

Worth the drive68%

Worth the drive. At Pago Pago on this hour the read is 68%. What earns it: peel speed at 12.6 km/h. What costs it: period cleanliness at 7.7 s.

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 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.

Pago Pago · 24 hours, local timelive data
00:0003:0006:0009:0012:0015:0018:0021:00
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
Pago Pago, American Samoa
Datum
MLLW
Range
0.97 m
Mean
0.43 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 · Pago PagoReef pass — a channel cut through the outer barrier reef
take-off0m3m6m9m12m15moffshoreinshore · tanβ 0.11
0.14 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 de200d8a0c9b…
Water over take-off
exposed
Break height
0.71 m
Peel speed
12.6 km/h
Wave power
8.4 kW/m

Worth the drive. At Pago Pago on this hour the read is 68%. What earns it: peel speed at 12.6 km/h. What costs it: period cleanliness at 7.7 s.

Every factor, re-weighted for this tide

  • Swell power8.4 kW/m · 8.4%
  • Peel speed12.6 km/h · 20.0%
  • Wind quality6.9 m/s 74° off · 7.2%
  • Tide window1.24 m over the take-off · 18.0%
  • Direction match25° off the 155° peel · 10.7%
  • Period cleanliness7.7 s · 3.7%

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 power8.4 kW/m · 8.4%

    weight 0.220

  • Peel speed12.6 km/h · 20.0%

    weight 0.200

  • Wind quality6.9 m/s 74° off · 7.2%

    weight 0.200

  • Tide window1.24 m over the take-off · 18.0%

    weight 0.180

  • Direction match25° off the 155° peel · 10.7%

    weight 0.120

  • Period cleanliness7.7 s · 3.7%

    weight 0.080

engine seal de200d8a0c9b4830a8cefde9b8cc4c8f5c5f8080915b25709c0b3007d8855e7eecc07bacefd2709694f8f5a6b301c765

  • Swell power

    P = 1/16 · rho · g · Hs² · Tp = 0.628 · 1.32² · 8 = 8.4 kW/m, against a 22 kW/m "serious day" reference.

  • Peel speed

    c = sqrt(g · depth) = sqrt(9.81 · 1.24 m) = 12.6 km/h over a 1.24 m take-off, with 0.71 m standing up. Full marks 8.5–19 km/h: slower is mush, faster than ~25 km/h is unridable.

  • Wind quality

    Wind is 74° off at 6.9 m/s. Alignment = 1 − (1 + cos 74°)/2 = 0.36; speed envelope at 6.9 m/s = 1.00. Product 0.36.

  • 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 180°, this break peels cleanly from 155°. 25° of error: inside 12° is full marks, past 75° the swell wraps the headland and does not arrive.

  • Period cleanliness

    Tp = 7.7 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

Snapshot generated 2026-10-04T19:09:21.263Z. Break orientation, reef slope and take-off depth come from this project's catalogue and are labelled as estimates, not survey data.

Pago Pago, Tutuila · Swellread