MARINE REPORT / 72 HOURS

Tumon Bay Snorkel Report Today

Guam · Updated Sat 16:41 (ChST) · Source: Snapshot

The skinny

Marginal Data updated Sat 16:41 (ChST)

Tumon Bay looks marginal today. The least-bad daylight window is around Sat 18:00, but waves is limiting the forecast.

Right now (forecast)

Poor · 1.8/10

Sat 17:00 (ChST)

Later today

Poor · 1.7/10

Sat 18:00 (ChST)

Next three days

Fair · 3.7/10

Tue 15:00 (ChST)

Model estimates using Open-Meteo; not observations or safety guarantees. Check official advisories and conditions at the beach.

Score: 1.7/10

Best time: Sat 18:00

Main risk: Waves

No useful morning window is showing yet.

Best afternoon signal: Sat 18:00 (Poor). Peak afternoon wind is about 11.1 m/s.

Email me when it is good

Sunrise

06:11

Sunset

18:00

Water

29.5°C

Max air

27.1°C

Sky

Cloudy

100% cloud

No good model window in the next 72 hours

Use the best-available section for the least-bad times.

3-day planner Best available Show data

3-day planner

Saturday

❌ Poor conditions

Main blocker: Waves

Sunday

❌ Poor conditions

Main blocker: Waves

Monday

❌ Poor conditions

Main blocker: Waves

Best available hours

  • Tue 15:00: Fair (0.37) · still limited by waves, tide/current
  • Tue 14:00: Fair (0.36) · still limited by waves, wind
  • Tue 12:00: Poor (0.33) · still limited by waves, wind

Why this verdict

Main blockers across the next 72 hours:

  • Waves (70 hours)
  • Tide/current (69 hours)
  • Wind (62 hours)

Jellyfish drift risk

Drift estimate from wind, swell, current and warm water.

Low · 34/100

Low drift risk now.

warm water supports seasonal jellyfish activity; surface drift/current is noticeable; local shoreline exposure is not mapped yet.

Sightings override the model: if you see small purple jellyfish with long trailing tentacles, treat them as sting-capable and give them space.

Upcoming high tides

Sat 22:00, Sun 14:00

Nearby alternatives in Guam

No nearby alternatives available.

Advanced forecast data

Viewing current forecast

Sat 17:00 – Tue 17:00 (ChST)

Previous day Yesterday

Snorkel Score (next 24h)

Best snorkel score is 0.17 around Sat 18:00; 0 of 24 hours are good, fair, or excellent.

Score trend, higher is better. Excellent ≥ 0.72, good 0.55–0.72, fair 0.35–0.55.

Conditions (24h trends)

Tap a chart to load just that series.

0/24 sampled hours stay at or below 0.36m (range 2.52m to 6.24m).

Wind is at or below 5.4m/s in 0/24 sampled hours (range 11.09 to 19.89m/s).

Tides range from 0.32m to 1.25m; 2 of 24 hours are in or near peak slack windows.

72-hour forecast overview
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Fair ⚠️ Fair
Fair ⚠️ Fair
Scoring methodology (for technical users)

We score each hour from 0 to 1 using daylight and these weighted components:

  • Wave height (35%): best below 0.36m, then decreases as it rises.
  • Wind speed (25%): best below 5.4m/s, lower is better.
  • Sea surface temperature (15%): best within 20.6°C to 30.4°C.
  • Tide and currents (15%): best around slack/high-tide windows.
  • Daylight (10%): visibility is better in daylight, so night hours score lower.
Detailed hourly data table
Time Wave (m) Wind (m/s) Sea temp (°C) Status
Sat 18:00 2.52 · high 11.09 · high 29.50 · good Poor
Sat 19:00 2.70 · high 11.12 · high 29.40 · good Poor
Sat 20:00 2.88 · high 11.47 · high 29.40 · good Poor
Sat 21:00 3.04 · high 12.52 · high 29.40 · good Poor
Sat 22:00 3.22 · high 13.71 · high 29.40 · good Poor
Sat 23:00 3.50 · high 14.69 · high 29.40 · good Poor
Sun 00:00 3.76 · high 14.38 · high 29.30 · good Poor
Sun 01:00 4.04 · high 14.67 · high 29.30 · good Poor
Sun 02:00 4.38 · high 15.35 · high 29.30 · good Poor
Sun 03:00 4.70 · high 17.17 · high 29.30 · good Poor
Sun 04:00 5.04 · high 17.86 · high 29.20 · good Poor
Sun 05:00 5.30 · high 16.94 · high 29.20 · good Poor
Sun 06:00 5.58 · high 19.89 · high 29.20 · good Poor
Sun 07:00 5.84 · high 16.35 · high 29.20 · good Poor
Sun 08:00 5.98 · high 19.47 · high 29.10 · good Poor
Sun 09:00 6.10 · high 17.40 · high 29.10 · good Poor
Sun 10:00 6.24 · high 17.88 · high 29.10 · good Poor
Sun 11:00 5.84 · high 16.64 · high 29.00 · good Poor
Sun 12:00 5.42 · high 16.46 · high 29.00 · good Poor
Sun 13:00 5.02 · high 16.63 · high 29.00 · good Poor
Sun 14:00 4.80 · high 16.88 · high 28.90 · good Poor
Sun 15:00 4.60 · high 15.55 · high 28.90 · good Poor
Sun 16:00 4.38 · high 14.98 · high 28.80 · good Poor
Sun 17:00 4.24 · high 14.66 · high 28.80 · good Poor
Sun 18:00 4.12 · high 13.61 · high 28.80 · good Poor
Sun 19:00 3.98 · high 13.52 · high 28.70 · good Poor
Sun 20:00 3.90 · high 12.31 · high 28.70 · good Poor
Sun 21:00 3.82 · high 13.10 · high 28.70 · good Poor
Sun 22:00 3.74 · high 12.14 · high 28.70 · good Poor
Sun 23:00 3.60 · high 11.39 · high 28.70 · good Poor
Mon 00:00 3.48 · high 10.63 · high 28.60 · good Poor
Mon 01:00 3.34 · high 10.02 · high 28.60 · good Poor
Mon 02:00 3.24 · high 11.47 · high 28.60 · good Poor
Mon 03:00 3.16 · high 10.65 · high 28.60 · good Poor
Mon 04:00 3.06 · high 10.54 · high 28.50 · good Poor
Mon 05:00 2.98 · high 9.55 · high 28.50 · good Poor
Mon 06:00 2.90 · high 9.46 · high 28.50 · good Poor
Mon 07:00 2.82 · high 9.95 · high 28.40 · good Poor
Mon 08:00 2.76 · high 10.20 · high 28.40 · good Poor
Mon 09:00 2.68 · high 9.13 · high 28.40 · good Poor
Mon 10:00 2.62 · high 9.19 · high 28.40 · good Poor
Mon 11:00 2.56 · high 11.34 · high 28.40 · good Poor
Mon 12:00 2.52 · high 10.30 · high 28.40 · good Poor
Mon 13:00 2.46 · high 11.65 · high 28.40 · good Poor
Mon 14:00 2.42 · high 10.37 · high 28.40 · good Poor
Mon 15:00 2.38 · high 10.64 · high 28.40 · good Poor
Mon 16:00 2.34 · high 9.40 · high 28.40 · good Poor
Mon 17:00 2.28 · high 8.04 · high 28.40 · good Poor
Mon 18:00 2.22 · high 7.57 · high 28.40 · good Poor
Mon 19:00 2.16 · high 6.62 · high 28.40 · good Poor
Mon 20:00 2.12 · high 4.83 · good 28.30 · good Poor
Mon 21:00 2.08 · high 7.43 · high 28.30 · good Poor
Mon 22:00 2.04 · high 6.34 · high 28.30 · good Poor
Mon 23:00 2.00 · high 5.35 · good 28.30 · good Poor
Tue 00:00 1.98 · high 5.91 · high 28.30 · good Poor
Tue 01:00 1.94 · high 4.95 · good 28.30 · good Poor
Tue 02:00 1.90 · high 5.34 · good 28.30 · good Poor
Tue 03:00 1.88 · high 5.29 · good 28.30 · good Poor
Tue 04:00 1.84 · high 5.12 · good 28.30 · good Poor
Tue 05:00 1.82 · high 5.13 · good 28.30 · good Poor
Tue 06:00 1.78 · high 5.60 · high 28.30 · good Poor
Tue 07:00 1.76 · high 5.81 · high 28.30 · good Poor
Tue 08:00 1.74 · high 6.22 · high 28.30 · good Poor
Tue 09:00 1.72 · high 6.31 · high 28.40 · good Poor
Tue 10:00 1.70 · high 6.61 · high 28.40 · good Poor
Tue 11:00 1.68 · high 6.24 · high 28.40 · good Poor
Tue 12:00 1.68 · high 6.01 · high 28.40 · good Poor
Tue 13:00 1.66 · high 5.85 · high 28.50 · good Poor
Tue 14:00 1.64 · high 5.44 · high 28.50 · good Fair
Tue 15:00 1.62 · high 5.03 · good 28.50 · good Fair