MARINE REPORT / 72 HOURS

Tumon Bay Snorkel Report Today

Guam · Updated Sat 20:08 (ChST) · Source: Snapshot

The skinny

Poor Data updated Sat 20:08 (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

Sat 21:00 (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

26.6°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 17:00: Fair (0.35) · still limited by waves, tide/current

Why this verdict

Main blockers across the next 72 hours:

  • Waves (70 hours)
  • Tide/current (69 hours)
  • Wind (60 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

Tue 21:00 – Fri 21:00 (ChST)

Previous day Yesterday Next day Live

Snorkel Score (selected 24h)

Best snorkel score is 0.43 around Wed 13:00; 9 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 0.74m to 0.94m).

Wind is at or below 5.4m/s in 24/24 sampled hours (range 0.05 to 2.38m/s).

Tides range from 0.09m to 0.77m; 2 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
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
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
Poor ❌ Limited
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
Fair ⚠️ Fair
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
Poor ❌ Limited
Poor ❌ Limited
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
Tue 21:00 0.92 · high 0.70 · good 29.70 · good Poor
Tue 22:00 0.94 · high 0.68 · good 29.60 · good Poor
Tue 23:00 0.94 · high 0.41 · good 29.60 · good Poor
Wed 00:00 0.94 · high 0.05 · good 29.50 · good Poor
Wed 01:00 0.94 · high 0.53 · good 29.50 · good Poor
Wed 02:00 0.94 · high 1.05 · good 29.50 · good Poor
Wed 03:00 0.88 · high 0.29 · good 29.40 · good Poor
Wed 04:00 0.88 · high 0.32 · good 29.40 · good Poor
Wed 05:00 0.88 · high 0.43 · good 29.40 · good Poor
Wed 06:00 0.88 · high 0.47 · good 29.40 · good Poor
Wed 07:00 0.88 · high 1.35 · good 29.40 · good Poor
Wed 08:00 0.88 · high 1.35 · good 29.50 · good Poor
Wed 09:00 0.86 · high 0.96 · good 29.50 · good Poor
Wed 10:00 0.86 · high 0.32 · good 29.50 · good Fair
Wed 11:00 0.84 · high 1.01 · good 29.60 · good Fair
Wed 12:00 0.84 · high 1.06 · good 29.70 · good Fair
Wed 13:00 0.82 · high 1.97 · good 29.80 · good Fair
Wed 14:00 0.80 · high 2.38 · good 29.90 · good Fair
Wed 15:00 0.80 · high 1.65 · good 30.00 · good Fair
Wed 16:00 0.78 · high 2.20 · good 30.00 · good Fair
Wed 17:00 0.76 · high 1.50 · good 30.00 · good Fair
Wed 18:00 0.76 · high 0.65 · good 29.90 · good Fair
Wed 19:00 0.74 · high 0.90 · good 29.80 · good Poor
Wed 20:00 0.74 · high 1.38 · good 29.70 · good Poor
Wed 21:00 0.76 · high 1.59 · good 29.60 · good Poor
Wed 22:00 0.76 · high 1.15 · good 29.60 · good Poor
Wed 23:00 0.74 · high 0.96 · good 29.50 · good Poor
Thu 00:00 0.70 · high 0.83 · good 29.50 · good Poor
Thu 01:00 0.70 · high 0.70 · good 29.50 · good Poor
Thu 02:00 0.70 · high 1.62 · good 29.50 · good Poor
Thu 03:00 0.70 · high 1.87 · good 29.40 · good Poor
Thu 04:00 0.70 · high 1.30 · good 29.40 · good Poor
Thu 05:00 0.70 · high 1.12 · good 29.40 · good Poor
Thu 06:00 0.72 · high 1.17 · good 29.40 · good Poor
Thu 07:00 0.72 · high 2.16 · good 29.40 · good Poor
Thu 08:00 0.72 · high 2.81 · good 29.40 · good Poor
Thu 09:00 0.72 · high 2.98 · good 29.40 · good Poor
Thu 10:00 0.72 · high 3.45 · good 29.40 · good Fair
Thu 11:00 0.72 · high 3.81 · good 29.50 · good Fair
Thu 12:00 0.72 · high 3.91 · good 29.50 · good Poor
Thu 13:00 0.72 · high 3.56 · good 29.60 · good Fair
Thu 14:00 0.74 · high 3.56 · good 29.70 · good Fair
Thu 15:00 0.74 · high 3.38 · good 29.80 · good Fair
Thu 16:00 0.76 · high 2.71 · good 29.80 · good Fair
Thu 17:00 0.76 · high 3.29 · good 29.80 · good Fair
Thu 18:00 0.76 · high 3.19 · good 29.70 · good Fair
Thu 19:00 0.76 · high 2.94 · good 29.70 · good Poor
Thu 20:00 0.76 · high 2.59 · good 29.60 · good Poor
Thu 21:00 0.76 · high 2.54 · good 29.50 · good Poor
Thu 22:00 0.76 · high 3.42 · good 29.50 · good Poor
Thu 23:00 0.76 · high 3.37 · good 29.50 · good Poor
Fri 00:00 0.78 · high 3.34 · good 29.40 · good Poor
Fri 01:00 0.78 · high 3.51 · good 29.40 · good Poor
Fri 02:00 0.76 · high 3.29 · good 29.40 · good Poor
Fri 03:00 0.76 · high 3.33 · good 29.30 · good Poor
Fri 04:00 0.76 · high 2.92 · good 29.30 · good Poor
Fri 05:00 0.76 · high 2.89 · good 29.30 · good Poor
Fri 06:00 0.76 · high 2.75 · good 29.30 · good Poor
Fri 07:00 0.76 · high 3.76 · good 29.30 · good Poor
Fri 08:00 0.76 · high 4.16 · good 29.30 · good Poor
Fri 09:00 0.78 · high 4.59 · good 29.40 · good Poor
Fri 10:00 0.78 · high 4.83 · good 29.40 · good Poor
Fri 11:00 0.78 · high 4.11 · good 29.40 · good Poor
Fri 12:00 0.80 · high 5.42 · high 29.50 · good Poor
Fri 13:00 0.80 · high 5.54 · high 29.50 · good Poor
Fri 14:00 0.80 · high 5.88 · high 29.60 · good Poor
Fri 15:00 0.82 · high 5.71 · high 29.60 · good Poor
Fri 16:00 0.82 · high 5.09 · good 29.60 · good Fair
Fri 17:00 0.82 · high 5.20 · good 29.60 · good Fair
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