MARINE REPORT / 72 HOURS

Tumon Bay Snorkel Report Today

Guam · Updated Sun 18:21 (ChST) · Source: Snapshot

The skinny

Poor Data updated Sun 18:21 (ChST)

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

Right now (forecast)

Poor · 0.0/10

Sun 21:00 (ChST)

Later today

No fresh data for this period.

Next three days

Fair · 4.1/10

Wed 16:00 (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

27.1°C

Max air

25.1°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

Sunday

❌ Poor conditions

Main blocker: Waves

Monday

❌ Poor conditions

Main blocker: Waves

Tuesday

⚠️ Fair conditions

Main blocker: Waves

Best available hours

  • Wed 16:00: Fair (0.41) · still limited by waves, tide/current
  • Tue 14:00: Fair (0.40) · still limited by waves, tide/current
  • Wed 17:00: Fair (0.38) · still limited by waves, tide/current

Why this verdict

Main blockers across the next 72 hours:

  • Waves (68 hours)
  • Tide/current (68 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

Tue 16:00, Wed 16:00

Nearby alternatives in Guam

No nearby alternatives available.

Advanced forecast data

Viewing historical data

Wed 21:00 – Sat 21:00 (ChST)

Previous day Yesterday Next day Live

Snorkel Score (selected 24h)

Best snorkel score is 0.42 around Thu 16:00; 3 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 1.1m).

Wind is at or below 5.4m/s in 23/24 sampled hours (range 2.28 to 5.55m/s).

Tides range from 0.24m to 0.87m; 1 of 24 hours are in or near peak slack windows.

72-hour historical overview
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
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Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Fair ⚠️ Fair
Fair ⚠️ Fair
Poor ❌ Limited
Poor ❌ Limited
Fair ⚠️ Fair
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
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Poor ❌ Limited
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Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Fair ⚠️ Fair
Fair ⚠️ Fair
Poor ❌ Limited
Poor ❌ Limited
Poor ❌ Limited
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
Poor ❌ Limited
Poor ❌ Limited
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
Wed 21:00 1.10 · high 2.73 · good 29.70 · good Poor
Wed 22:00 1.08 · high 2.82 · good 29.70 · good Poor
Wed 23:00 1.06 · high 2.33 · good 29.60 · good Poor
Thu 00:00 1.06 · high 2.73 · good 29.60 · good Poor
Thu 01:00 1.04 · high 2.55 · good 29.60 · good Poor
Thu 02:00 1.02 · high 3.07 · good 29.50 · good Poor
Thu 03:00 1.00 · high 2.28 · good 29.50 · good Poor
Thu 04:00 0.98 · high 2.44 · good 29.50 · good Poor
Thu 05:00 0.96 · high 2.51 · good 29.50 · good Poor
Thu 06:00 0.96 · high 2.34 · good 29.60 · good Poor
Thu 07:00 0.94 · high 3.16 · good 29.60 · good Poor
Thu 08:00 0.92 · high 4.11 · good 29.60 · good Poor
Thu 09:00 0.92 · high 4.00 · good 29.70 · good Poor
Thu 10:00 0.90 · high 4.03 · good 29.70 · good Poor
Thu 11:00 0.90 · high 4.05 · good 29.80 · good Poor
Thu 12:00 0.88 · high 4.59 · good 29.90 · good Poor
Thu 13:00 0.88 · high 5.03 · good 30.00 · good Poor
Thu 14:00 0.88 · high 5.38 · good 30.10 · good Poor
Thu 15:00 0.86 · high 5.55 · high 30.20 · good Poor
Thu 16:00 0.86 · high 4.62 · good 30.20 · good Fair
Thu 17:00 0.86 · high 4.60 · good 30.20 · good Fair
Thu 18:00 0.84 · high 4.00 · good 30.20 · good Fair
Thu 19:00 0.84 · high 3.46 · good 30.10 · good Poor
Thu 20:00 0.84 · high 3.51 · good 30.00 · good Poor
Thu 21:00 0.90 · high 1.20 · good 29.90 · good Poor
Thu 22:00 0.90 · high 3.41 · good 29.50 · good Poor
Thu 23:00 0.90 · high 2.99 · good 29.50 · good Poor
Fri 00:00 0.90 · high 3.15 · good 29.50 · good Poor
Fri 01:00 0.90 · high 3.51 · good 29.50 · good Poor
Fri 02:00 0.90 · high 2.90 · good 29.50 · good Poor
Fri 03:00 0.90 · high 2.74 · good 29.50 · good Poor
Fri 04:00 0.90 · high 2.77 · good 29.50 · good Poor
Fri 05:00 0.90 · high 3.03 · good 29.50 · good Poor
Fri 06:00 0.88 · high 2.71 · good 29.50 · good Poor
Fri 07:00 0.88 · high 3.28 · good 29.50 · good Poor
Fri 08:00 0.88 · high 3.95 · good 29.50 · good Poor
Fri 09:00 0.88 · high 3.80 · good 29.50 · good Poor
Fri 10:00 0.86 · high 2.90 · good 29.50 · good Fair
Fri 11:00 0.86 · high 2.72 · good 29.50 · good Fair
Fri 12:00 0.84 · high 4.86 · good 29.50 · good Poor
Fri 13:00 0.84 · high 4.68 · good 29.60 · good Poor
Fri 14:00 0.84 · high 5.24 · good 29.60 · good Fair
Fri 15:00 0.86 · high 4.96 · good 29.70 · good Poor
Fri 16:00 0.86 · high 5.02 · good 29.70 · good Poor
Fri 17:00 0.86 · high 3.26 · good 29.70 · good Poor
Fri 18:00 0.86 · high 3.15 · good 29.60 · good Poor
Fri 19:00 0.86 · high 2.95 · good 29.60 · good Poor
Fri 20:00 0.86 · high 4.15 · good 29.60 · good Poor
Fri 21:00 0.82 · high 3.89 · good 29.60 · good Poor
Fri 22:00 0.82 · high 3.37 · good 29.50 · good Poor
Fri 23:00 0.82 · high 3.31 · good 29.50 · good Poor
Sat 00:00 0.78 · high 2.90 · good 29.50 · good Poor
Sat 01:00 0.78 · high 3.13 · good 29.50 · good Poor
Sat 02:00 0.78 · high 3.03 · good 29.40 · good Poor
Sat 03:00 0.78 · high 2.91 · good 29.40 · good Poor
Sat 04:00 0.78 · high 3.10 · good 29.40 · good Poor
Sat 05:00 0.78 · high 3.07 · good 29.40 · good Poor
Sat 06:00 0.76 · high 2.77 · good 29.40 · good Poor
Sat 07:00 0.76 · high 2.65 · good 29.50 · good Poor
Sat 08:00 0.76 · high 1.38 · good 29.50 · good Poor
Sat 09:00 0.74 · high 1.69 · good 29.50 · good Poor
Sat 10:00 0.74 · high 3.72 · good 29.50 · good Fair
Sat 11:00 0.74 · high 4.14 · good 29.60 · good Fair
Sat 12:00 0.74 · high 3.20 · good 29.60 · good Poor
Sat 13:00 0.74 · high 3.40 · good 29.60 · good Poor
Sat 14:00 0.74 · high 3.25 · good 29.60 · good Poor
Sat 15:00 0.76 · high 2.87 · good 29.70 · good Fair
Sat 16:00 0.76 · high 5.06 · good 29.70 · good Fair
Sat 17:00 0.74 · high 3.48 · good 29.70 · good Fair
Sat 18:00 0.74 · high 1.55 · good 29.60 · good Fair
Sat 19:00 0.72 · high 1.53 · good 29.60 · good Poor
Sat 20:00 0.72 · high 1.77 · good 29.60 · good Poor