MARINE REPORT / 72 HOURS

Tumon Bay Snorkel Report Today

Guam · Updated Sun 12:07 (ChST) · Source: Snapshot

The skinny

Marginal Data updated Sun 12:07 (ChST)

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

Right now (forecast)

Poor · 1.7/10

Sun 12:00 (ChST)

Later today

Poor · 1.7/10

Sun 13:00 (ChST)

Next three days

Fair · 3.8/10

Tue 14:00 (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: Sun 18:00

Main risk: Waves

No useful morning window is showing yet.

Best afternoon signal: Sun 13:00 (Poor). Peak afternoon wind is about 14.8 m/s.

Email me when it is good

Sunrise

06:11

Sunset

18:00

Water

28.2°C

Max air

26.7°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

Sunday

❌ Poor conditions

Main blocker: Waves

Monday

❌ Poor conditions

Main blocker: Waves

Tuesday

⚠️ Fair conditions

Main blocker: Waves

Best available hours

  • Tue 14:00: Fair (0.38) · still limited by waves, tide/current
  • Tue 17:00: Fair (0.38) · still limited by waves, tide/current
  • Tue 16:00: Poor (0.35) · still limited by waves, tide/current

Why this verdict

Main blockers across the next 72 hours:

  • Waves (71 hours)
  • Tide/current (71 hours)
  • Darkness (47 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

Tue 16:00

Nearby alternatives in Guam

No nearby alternatives available.

Advanced forecast data

Viewing historical data

Fri 12:00 – Mon 12:00 (ChST)

Previous day Yesterday Next day Live

Snorkel Score (selected 24h)

Best snorkel score is 0.3 around Fri 16:00; 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 1.04m to 2.86m).

Wind is at or below 5.4m/s in 0/24 sampled hours (range 5.68 to 11.58m/s).

Tides range from 0.12m to 0.89m; 2 of 24 hours are in or near peak slack windows.

72-hour historical overview
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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
Fri 12:00 1.04 · high 7.16 · high 30.00 · good Poor
Fri 13:00 1.06 · high 7.95 · high 30.00 · good Poor
Fri 14:00 1.08 · high 7.85 · high 30.00 · good Poor
Fri 15:00 1.12 · high 7.77 · high 30.00 · good Poor
Fri 16:00 1.14 · high 7.68 · high 30.00 · good Poor
Fri 17:00 1.14 · high 7.54 · high 30.00 · good Poor
Fri 18:00 1.14 · high 6.66 · high 30.00 · good Poor
Fri 19:00 1.14 · high 5.68 · high 30.00 · good Poor
Fri 20:00 1.14 · high 5.87 · high 29.90 · good Poor
Fri 21:00 1.28 · high 5.89 · high 30.00 · good Poor
Fri 22:00 1.30 · high 7.71 · high 30.00 · good Poor
Fri 23:00 1.32 · high 7.45 · high 30.00 · good Poor
Sat 00:00 1.34 · high 6.68 · high 30.00 · good Poor
Sat 01:00 1.36 · high 8.05 · high 29.90 · good Poor
Sat 02:00 1.38 · high 7.50 · high 29.90 · good Poor
Sat 03:00 1.40 · high 7.86 · high 29.90 · good Poor
Sat 04:00 2.64 · high 10.43 · high 29.90 · good Poor
Sat 05:00 2.66 · high 10.59 · high 29.90 · good Poor
Sat 06:00 2.70 · high 10.46 · high 29.90 · good Poor
Sat 07:00 2.72 · high 10.48 · high 29.90 · good Poor
Sat 08:00 2.76 · high 11.39 · high 29.90 · good Poor
Sat 09:00 2.80 · high 10.95 · high 29.90 · good Poor
Sat 10:00 2.84 · high 11.40 · high 29.90 · good Poor
Sat 11:00 2.86 · high 11.58 · high 29.90 · good Poor
Sat 12:00 2.90 · high 12.73 · high 29.90 · good Poor
Sat 13:00 2.92 · high 12.56 · high 30.00 · good Poor
Sat 14:00 2.94 · high 11.81 · high 30.00 · good Poor
Sat 15:00 2.96 · high 10.76 · high 30.00 · good Poor
Sat 16:00 2.98 · high 11.65 · high 30.00 · good Poor
Sat 17:00 3.02 · high 9.96 · high 30.00 · good Poor
Sat 18:00 3.04 · high 10.71 · high 30.00 · good Poor
Sat 19:00 3.08 · high 9.58 · high 30.00 · good Poor
Sat 20:00 3.04 · high 10.11 · high 29.90 · good Poor
Sat 21:00 2.54 · high 9.69 · high 29.70 · good Poor
Sat 22:00 2.52 · high 9.70 · high 29.70 · good Poor
Sat 23:00 2.54 · high 8.34 · high 29.70 · good Poor
Sun 00:00 2.58 · high 9.86 · high 29.70 · good Poor
Sun 01:00 2.60 · high 9.22 · high 29.70 · good Poor
Sun 02:00 3.12 · high 11.04 · high 29.70 · good Poor
Sun 03:00 3.12 · high 10.15 · high 29.70 · good Poor
Sun 04:00 3.10 · high 10.86 · high 29.70 · good Poor
Sun 05:00 3.08 · high 10.36 · high 29.70 · good Poor
Sun 06:00 3.06 · high 10.77 · high 29.70 · good Poor
Sun 07:00 3.04 · high 10.64 · high 29.70 · good Poor
Sun 08:00 3.06 · high 11.41 · high 29.70 · good Poor
Sun 09:00 3.06 · high 11.75 · high 29.70 · good Poor
Sun 10:00 3.08 · high 11.81 · high 29.70 · good Poor
Sun 11:00 3.10 · high 12.11 · high 29.70 · good Poor
Sun 12:00 3.10 · high 13.02 · high 29.70 · good Poor
Sun 13:00 3.12 · high 12.25 · high 29.70 · good Poor
Sun 14:00 3.14 · high 12.04 · high 29.70 · good Poor
Sun 15:00 3.16 · high 11.85 · high 29.70 · good Poor
Sun 16:00 3.18 · high 11.89 · high 29.70 · good Poor
Sun 17:00 3.12 · high 11.60 · high 29.70 · good Poor
Sun 18:00 3.08 · high 9.10 · high 29.70 · good Poor
Sun 19:00 3.02 · high 9.93 · high 29.70 · good Poor
Sun 20:00 2.98 · high 9.88 · high 29.60 · good Poor
Sun 21:00 3.02 · high 9.44 · high 29.70 · good Poor
Sun 22:00 3.00 · high 10.08 · high 29.70 · good Poor
Sun 23:00 3.00 · high 9.51 · high 29.70 · good Poor
Mon 00:00 3.02 · high 9.54 · high 29.60 · good Poor
Mon 01:00 3.02 · high 9.46 · high 29.60 · good Poor
Mon 02:00 3.00 · high 9.03 · high 29.60 · good Poor
Mon 03:00 2.98 · high 9.20 · high 29.60 · good Poor
Mon 04:00 3.08 · high 9.06 · high 29.60 · good Poor
Mon 05:00 3.06 · high 9.44 · high 29.60 · good Poor
Mon 06:00 3.06 · high 9.12 · high 29.60 · good Poor
Mon 07:00 3.04 · high 9.83 · high 29.60 · good Poor
Mon 08:00 3.04 · high 9.59 · high 29.60 · good Poor
Mon 09:00 3.02 · high 10.11 · high 29.60 · good Poor
Mon 10:00 3.02 · high 10.18 · high 29.60 · good Poor
Mon 11:00 3.00 · high 11.07 · high 29.60 · good Poor