SnorkelForecast.com

Tumon Bay Snorkel Report Today

Guam · Updated Tue 04:16 (ChST) · Source: Snapshot · Showing fallback/stale data

The skinny

Marginal Report Wed 18:55

Tumon Bay looks marginal today. The least-bad daylight window is around Fri 13:00, but waves is limiting the forecast.

Score: 4.7/10

Best time: Fri 13:00

Main risk: Waves

No useful morning window is showing yet.

No useful afternoon window is showing yet.

Email me when it is good

Sunrise

06:03

Sunset

18:51

Water

29.4°C

Max air

27.0°C

Sky

Cloudy

99% cloud

No safe 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

Wednesday

❌ poor conditions

Main blocker: Waves

Thursday

⚠️ fair conditions

Main blocker: Waves

Friday

⚠️ fair conditions

Main blocker: Waves

Best available hours

  • Fri 03:00 — Fair (0.48) · still limited by waves, tide/current
  • Thu 02:00 — Fair (0.47) · still limited by waves
  • Fri 01:00 — Fair (0.41) · still limited by waves, tide/current

Why this verdict

Main blockers across the next 72 hours:

  • Waves (43 hours)
  • Tide/current (38 hours)
  • Darkness (30 hours)

Jellyfish drift risk

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

Low · 34/100

Low peak drift risk around Wed 20:00.

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

Next early morning high tide: Wed 15:00

Wed 15:00, Thu 06:00, Thu 16:00

Nearby alternatives in Guam

No nearby alternatives available.

Advanced forecast data

Viewing historical data

Mon 08:00 – Thu 08:00 (ChST)

Previous day Yesterday Next day Live

Snorkel Score (selected 24h)

Best snorkel score is 0.21 around Tue 17:00; 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 3.3m to 5.52m).

Wind is at or below 5.4m/s in 0/24 sampled hours (range 8.99 to 56.9m/s).

Tides range from 0.67m to 1.16m; 1 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 and safety gate (outside daylight scores lower).
Detailed hourly data table
Time Wave (m) Wind (m/s) Sea temp (°C) Status
Mon 08:00 5.52 · high 56.90 · high 29.30 · good poor
Mon 09:00 5.24 · high 56.80 · high 29.30 · good poor
Mon 10:00 4.82 · high 14.44 · high 29.20 · good poor
Mon 11:00 4.64 · high 13.00 · high 29.10 · good poor
Mon 12:00 4.46 · high 13.21 · high 29.10 · good poor
Mon 13:00 4.28 · high 12.00 · high 29.10 · good poor
Mon 14:00 4.10 · high 11.80 · high 29.10 · good poor
Mon 15:00 3.92 · high 10.51 · high 29.10 · good poor
Mon 16:00 3.84 · high 10.30 · high 29.10 · good poor
Mon 17:00 3.76 · high 10.45 · high 29.10 · good poor
Mon 18:00 3.68 · high 10.26 · high 29.10 · good poor
Mon 19:00 3.68 · high 9.23 · high 29.10 · good poor
Mon 20:00 3.66 · high 9.54 · high 29.10 · good poor
Mon 21:00 3.66 · high 10.37 · high 29.00 · good poor
Mon 22:00 3.64 · high 10.61 · high 29.00 · good poor
Mon 23:00 3.64 · high 11.04 · high 29.00 · good poor
Tue 00:00 3.62 · high 10.92 · high 29.00 · good poor
Tue 01:00 3.58 · high 12.16 · high 29.00 · good poor
Tue 02:00 3.56 · high 11.90 · high 29.00 · good poor
Tue 03:00 3.52 · high 11.02 · high 29.10 · good poor
Tue 04:00 3.46 · high 9.97 · high 29.10 · good poor
Tue 05:00 3.42 · high 10.24 · high 29.10 · good poor
Tue 06:00 3.36 · high 10.02 · high 29.10 · good poor
Tue 07:00 3.30 · high 8.99 · high 29.10 · good poor
Tue 08:00 3.22 · high 7.87 · high 29.10 · good poor
Tue 09:00 3.16 · high 7.46 · high 29.10 · good poor
Tue 10:00 3.14 · high 6.01 · high 29.00 · good poor
Tue 11:00 3.12 · high 7.77 · high 29.00 · good poor
Tue 12:00 3.10 · high 5.81 · high 29.00 · good poor
Tue 13:00 3.08 · high 5.50 · high 29.00 · good poor
Tue 14:00 3.04 · high 5.41 · high 29.00 · good poor
Tue 15:00 3.02 · high 5.96 · high 29.00 · good poor
Tue 16:00 2.98 · high 6.57 · high 29.00 · good poor
Tue 17:00 2.96 · high 6.30 · high 29.00 · good poor
Tue 18:00 2.92 · high 5.12 · good 29.00 · good poor
Tue 19:00 2.88 · high 5.27 · good 29.00 · good poor
Tue 20:00 2.84 · high 4.83 · good 29.00 · good poor
Tue 21:00 2.80 · high 5.80 · high 29.00 · good poor
Tue 22:00 2.78 · high 7.07 · high 29.10 · good poor
Tue 23:00 2.74 · high 7.00 · high 29.10 · good poor
Wed 00:00 2.72 · high 6.91 · high 29.10 · good poor
Wed 01:00 2.70 · high 6.10 · high 29.10 · good poor
Wed 02:00 2.66 · high 6.95 · high 29.10 · good poor
Wed 03:00 2.64 · high 7.06 · high 29.10 · good poor
Wed 04:00 2.60 · high 7.15 · high 29.10 · good poor
Wed 05:00 2.58 · high 6.73 · high 29.10 · good poor
Wed 06:00 2.54 · high 5.78 · high 29.10 · good poor
Wed 07:00 2.50 · high 5.94 · high 29.10 · good poor
Wed 08:00 2.46 · high 5.06 · good 29.10 · good poor
Wed 09:00 2.42 · high 4.79 · good 29.10 · good poor
Wed 10:00 2.38 · high 3.74 · good 29.10 · good poor
Wed 11:00 2.36 · high 3.55 · good 29.10 · good poor
Wed 12:00 2.32 · high 3.30 · good 29.10 · good poor
Wed 13:00 2.30 · high 2.86 · good 29.10 · good poor
Wed 14:00 2.28 · high 3.87 · good 29.10 · good poor
Wed 15:00 2.26 · high 2.04 · good 29.10 · good poor
Wed 16:00 2.24 · high 1.15 · good 29.10 · good poor
Wed 17:00 2.24 · high 4.04 · good 29.10 · good poor
Wed 18:00 2.22 · high 1.63 · good 29.10 · good poor
Wed 19:00 2.20 · high 0.96 · good 29.10 · good poor
Wed 20:00 2.18 · high 1.32 · good 29.10 · good poor
Wed 21:00 2.16 · high 3.36 · good 29.10 · good poor
Wed 22:00 2.16 · high 2.94 · good 29.10 · good poor
Wed 23:00 2.16 · high 3.56 · good 29.20 · good poor
Thu 00:00 2.16 · high 2.26 · good 29.20 · good fair
Thu 01:00 2.16 · high 1.52 · good 29.30 · good fair
Thu 02:00 2.14 · high 2.28 · good 29.50 · good fair
Thu 03:00 2.14 · high 2.45 · good 29.60 · good fair
Thu 04:00 2.14 · high 2.48 · good 29.80 · good fair
Thu 05:00 2.14 · high 2.50 · good 29.90 · good fair
Thu 06:00 2.14 · high 2.28 · good 29.90 · good fair
Thu 07:00 2.16 · high 1.92 · good 29.90 · good fair