SnorkelForecast.com

Tumon Bay Snorkel Report Today

Guam · Updated Tue 04:16 (ChST) · Source: Snapshot

The skinny

Marginal Report Tue 19:14

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

06:02

Sunset

18:51

Water

29.2°C

Max air

28.1°C

Sky

Clear

2% 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

Tuesday

❌ poor conditions

Main blocker: Waves

Wednesday

⚠️ fair conditions

Main blocker: Waves

Thursday

⚠️ fair conditions

Main blocker: Waves

Best available hours

  • Fri 03:00 — Fair (0.48) · still limited by waves, tide/current
  • Wed 08:00 — Fair (0.47) · still limited by waves, tide/current
  • Thu 02:00 — Fair (0.47) · still limited by waves

Why this verdict

Main blockers across the next 72 hours:

  • Waves (66 hours)
  • Tide/current (61 hours)
  • Darkness (44 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

Next early morning high tide: Tue 15:00

Tue 15:00, Wed 05:00, Wed 15:00, Thu 06:00, Thu 16:00

Nearby alternatives in Guam

No nearby alternatives available.

Advanced forecast data

Viewing historical data

Wed 09:00 – Sat 09:00 (ChST)

Previous day Yesterday Next day Live

Snorkel Score (selected 24h)

Best snorkel score is 0.31 around Thu 13:00; 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 1.18m to 1.38m).

Wind is at or below 5.4m/s in 14/24 sampled hours (range 2.91 to 7.27m/s).

Tides range from 0.16m to 1.11m; 2 of 24 hours are in or near peak slack windows.

72-hour historical overview
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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 and safety gate (outside daylight scores lower).
Detailed hourly data table
Time Wave (m) Wind (m/s) Sea temp (°C) Status
Wed 09:00 1.34 · high 2.91 · good 29.00 · good poor
Wed 10:00 1.32 · high 3.16 · good 29.00 · good poor
Wed 11:00 1.28 · high 4.18 · good 29.00 · good poor
Wed 12:00 1.26 · high 4.81 · good 29.00 · good poor
Wed 13:00 1.24 · high 4.75 · good 29.00 · good poor
Wed 14:00 1.20 · high 3.58 · good 29.00 · good poor
Wed 15:00 1.18 · high 4.81 · good 28.90 · good poor
Wed 16:00 1.18 · high 4.30 · good 28.90 · good poor
Wed 17:00 1.18 · high 3.75 · good 28.90 · good poor
Wed 18:00 1.18 · high 3.76 · good 28.90 · good poor
Wed 19:00 1.20 · high 4.56 · good 28.90 · good poor
Wed 20:00 1.22 · high 4.41 · good 28.90 · good poor
Wed 21:00 1.24 · high 4.30 · good 28.90 · good poor
Wed 22:00 1.26 · high 4.65 · good 28.90 · good poor
Wed 23:00 1.26 · high 5.59 · high 28.90 · good poor
Thu 00:00 1.28 · high 6.51 · high 28.90 · good poor
Thu 01:00 1.30 · high 6.80 · high 28.90 · good poor
Thu 02:00 1.32 · high 6.70 · high 29.00 · good poor
Thu 03:00 1.34 · high 7.27 · high 29.00 · good poor
Thu 04:00 1.36 · high 6.78 · high 29.00 · good poor
Thu 05:00 1.36 · high 6.80 · high 29.10 · good poor
Thu 06:00 1.38 · high 6.77 · high 29.10 · good poor
Thu 07:00 1.36 · high 6.60 · high 29.10 · good poor
Thu 08:00 1.34 · high 5.88 · high 29.10 · good poor
Thu 09:00 1.32 · high 5.09 · good 29.00 · good poor
Thu 10:00 1.30 · high 4.30 · good 29.00 · good poor
Thu 11:00 1.26 · high 4.81 · good 29.00 · good poor
Thu 12:00 1.24 · high 4.08 · good 29.00 · good poor
Thu 13:00 1.22 · high 3.08 · good 29.00 · good poor
Thu 14:00 1.22 · high 3.23 · good 28.90 · good poor
Thu 15:00 1.20 · high 3.27 · good 28.90 · good poor
Thu 16:00 1.20 · high 3.96 · good 28.90 · good poor
Thu 17:00 1.18 · high 3.64 · good 28.90 · good poor
Thu 18:00 1.18 · high 4.20 · good 28.90 · good poor
Thu 19:00 1.18 · high 3.59 · good 28.90 · good poor
Thu 20:00 1.16 · high 4.10 · good 28.90 · good poor
Thu 21:00 1.16 · high 4.85 · good 28.90 · good poor
Thu 22:00 1.16 · high 5.98 · high 28.90 · good poor
Thu 23:00 1.16 · high 5.59 · high 28.90 · good poor
Fri 00:00 1.16 · high 5.91 · high 28.90 · good poor
Fri 01:00 1.16 · high 6.07 · high 29.00 · good poor
Fri 02:00 1.14 · high 6.28 · high 29.00 · good poor
Fri 03:00 1.14 · high 5.74 · high 29.00 · good poor
Fri 04:00 1.10 · high 5.37 · good 29.10 · good poor
Fri 05:00 1.08 · high 5.71 · high 29.10 · good poor
Fri 06:00 1.04 · high 5.06 · good 29.10 · good poor
Fri 07:00 1.02 · high 4.98 · good 29.10 · good poor
Fri 08:00 1.00 · high 4.85 · good 29.10 · good fair
Fri 09:00 0.98 · high 3.80 · good 29.10 · good poor
Fri 10:00 0.96 · high 3.46 · good 29.10 · good poor
Fri 11:00 0.96 · high 2.60 · good 29.00 · good poor
Fri 12:00 0.94 · high 4.48 · good 29.00 · good poor
Fri 13:00 0.94 · high 2.80 · good 29.00 · good poor
Fri 14:00 0.92 · high 3.07 · good 29.00 · good poor
Fri 15:00 0.92 · high 2.74 · good 29.00 · good poor
Fri 16:00 0.92 · high 2.45 · good 29.00 · good poor
Fri 17:00 0.90 · high 3.22 · good 29.00 · good poor
Fri 18:00 0.90 · high 3.40 · good 29.00 · good poor
Fri 19:00 0.90 · high 2.60 · good 29.00 · good poor
Fri 20:00 0.88 · high 2.13 · good 29.00 · good poor
Fri 21:00 0.88 · high 3.64 · good 29.00 · good poor
Fri 22:00 0.88 · high 3.61 · good 28.90 · good poor
Fri 23:00 0.86 · high 4.40 · good 29.00 · good poor
Sat 00:00 0.86 · high 4.60 · good 29.00 · good poor
Sat 01:00 0.86 · high 4.56 · good 29.00 · good poor
Sat 02:00 0.88 · high 4.77 · good 29.10 · good poor
Sat 03:00 0.88 · high 5.32 · good 29.20 · good poor
Sat 04:00 0.88 · high 5.02 · good 29.20 · good poor
Sat 05:00 0.90 · high 5.01 · good 29.30 · good poor
Sat 06:00 0.88 · high 4.85 · good 29.10 · good poor
Sat 07:00 0.88 · high 4.44 · good 29.10 · good poor
Sat 08:00 0.86 · high 4.17 · good 29.10 · good fair