MARINE REPORT / 72 HOURS

Tumon Bay Snorkel Report Today

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

The skinny

Poor Data updated Sat 16:41 (ChST)

Tumon Bay has no good model window later today. Check the three-day outlook and official beach advisories.

Right now (forecast)

Poor · 1.7/10

Sat 18:00 (ChST)

Later today

No fresh data for this period.

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: 0.0/10

Best time: -

Main risk: Waves

No useful morning window is showing yet.

No useful afternoon window is showing yet.

Email me when it is good

Sunrise

06:11

Sunset

18:00

Water

29.4°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 (69 hours)
  • Tide/current (68 hours)
  • Wind (61 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 historical data

Fri 18:00 – Mon 18:00 (ChST)

Previous day Yesterday Next day Live

Snorkel Score (selected 24h)

Best snorkel score is 0.37 around Fri 18:00; 1 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 0.84m to 1.26m).

Wind is at or below 5.4m/s in 16/24 sampled hours (range 3.0 to 6.99m/s).

Tides range from 0.16m to 0.78m; 2 of 24 hours are in or near peak slack windows.

72-hour historical overview
Fair ⚠️ Fair
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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 18:00 0.84 · high 5.20 · good 29.60 · good Fair
Fri 19:00 0.84 · high 4.60 · good 29.50 · good Poor
Fri 20:00 0.86 · high 4.46 · good 29.40 · good Poor
Fri 21:00 0.92 · high 4.85 · good 29.40 · good Poor
Fri 22:00 0.94 · high 4.92 · good 29.40 · good Poor
Fri 23:00 0.96 · high 4.61 · good 29.30 · good Poor
Sat 00:00 0.96 · high 4.28 · good 29.30 · good Poor
Sat 01:00 0.98 · high 3.91 · good 29.30 · good Poor
Sat 02:00 1.00 · high 3.83 · good 29.30 · good Poor
Sat 03:00 1.00 · high 4.36 · good 29.20 · good Poor
Sat 04:00 1.02 · high 4.50 · good 29.20 · good Poor
Sat 05:00 1.02 · high 3.31 · good 29.20 · good Poor
Sat 06:00 1.04 · high 3.00 · good 29.20 · good Poor
Sat 07:00 1.04 · high 3.60 · good 29.20 · good Poor
Sat 08:00 1.04 · high 5.03 · good 29.20 · good Poor
Sat 09:00 1.04 · high 4.74 · good 29.20 · good Poor
Sat 10:00 1.04 · high 6.04 · high 29.20 · good Poor
Sat 11:00 1.06 · high 5.97 · high 29.30 · good Poor
Sat 12:00 1.06 · high 6.32 · high 29.30 · good Poor
Sat 13:00 1.08 · high 6.61 · high 29.40 · good Poor
Sat 14:00 1.12 · high 6.99 · high 29.50 · good Poor
Sat 15:00 1.16 · high 6.83 · high 29.50 · good Poor
Sat 16:00 1.20 · high 5.63 · high 29.50 · good Poor
Sat 17:00 1.26 · high 5.71 · high 29.50 · good Poor
Sat 18:00 1.34 · high 5.48 · high 29.50 · good Poor
Sat 19:00 1.30 · high 3.92 · good 29.30 · good Poor
Sat 20:00 1.34 · high 2.11 · good 29.30 · good Poor
Sat 21:00 1.40 · high 5.32 · good 29.30 · good Poor
Sat 22:00 1.44 · high 4.68 · good 29.20 · good Poor
Sat 23:00 1.52 · high 5.85 · high 29.20 · good Poor
Sun 00:00 1.62 · high 7.20 · high 29.20 · good Poor
Sun 01:00 1.70 · high 7.31 · high 29.20 · good Poor
Sun 02:00 1.84 · high 6.94 · high 29.20 · good Poor
Sun 03:00 1.96 · high 8.14 · high 29.10 · good Poor
Sun 04:00 2.10 · high 7.83 · high 29.10 · good Poor
Sun 05:00 2.22 · high 4.80 · good 29.10 · good Poor
Sun 06:00 2.32 · high 6.17 · high 29.10 · good Poor
Sun 07:00 2.44 · high 5.91 · high 29.10 · good Poor
Sun 08:00 1.98 · high 11.34 · high 29.10 · good Poor
Sun 09:00 2.10 · high 11.59 · high 29.00 · good Poor
Sun 10:00 2.20 · high 13.86 · high 29.00 · good Poor
Sun 11:00 2.32 · high 15.14 · high 29.00 · good Poor
Sun 12:00 2.42 · high 14.85 · high 29.00 · good Poor
Sun 13:00 2.54 · high 15.75 · high 29.00 · good Poor
Sun 14:00 2.64 · high 15.97 · high 29.00 · good Poor
Sun 15:00 2.74 · high 17.57 · high 28.90 · good Poor
Sun 16:00 2.84 · high 20.75 · high 28.90 · good Poor
Sun 17:00 3.00 · high 23.52 · high 28.90 · good Poor
Sun 18:00 3.16 · high 20.34 · high 28.90 · good Poor
Sun 19:00 3.32 · high 17.25 · high 28.90 · good Poor
Sun 20:00 4.20 · high 22.80 · high 29.20 · good Poor
Sun 21:00 3.92 · high 20.55 · high 29.20 · good Poor
Sun 22:00 3.66 · high 17.95 · high 29.20 · good Poor
Sun 23:00 3.46 · high 16.95 · high 29.20 · good Poor
Mon 00:00 3.26 · high 15.59 · high 29.10 · good Poor
Mon 01:00 3.06 · high 14.37 · high 29.10 · good Poor
Mon 02:00 3.02 · high 13.33 · high 29.10 · good Poor
Mon 03:00 2.96 · high 12.63 · high 29.10 · good Poor
Mon 04:00 2.92 · high 12.12 · high 29.10 · good Poor
Mon 05:00 2.86 · high 11.61 · high 29.10 · good Poor
Mon 06:00 2.78 · high 12.33 · high 29.00 · good Poor
Mon 07:00 2.72 · high 11.42 · high 29.00 · good Poor
Mon 08:00 2.68 · high 12.18 · high 29.00 · good Poor
Mon 09:00 3.16 · high 11.66 · high 29.00 · good Poor
Mon 10:00 3.06 · high 11.61 · high 29.00 · good Poor
Mon 11:00 3.06 · high 11.97 · high 29.00 · good Poor
Mon 12:00 3.04 · high 12.09 · high 29.00 · good Poor
Mon 13:00 3.04 · high 11.08 · high 29.00 · good Poor
Mon 14:00 2.96 · high 10.39 · high 28.90 · good Poor
Mon 15:00 2.86 · high 9.97 · high 28.90 · good Poor
Mon 16:00 2.78 · high 9.73 · high 28.90 · good Poor
Mon 17:00 2.70 · high 8.54 · high 28.90 · good Poor