Tumon Bay Sea Temperature

Updated Wed 11:45 (Pacific/Guam)

Guam · Forecast updated Aug 12, 2026, 11:45 UTC

Current Sea Temperature

29.4°C

84.9°F

Very warm water

Versus this month's average

Close to average

The August average in our archive is 29.5°C (85.2°F).

Recent trend

Cooling by 0.4°C

Seven-day average: 29.4°C, versus 29.8°C in the prior seven days.

What to wear

Very warm water

Swimwear is usually enough; a rash guard adds sun protection.

Cold tolerance varies. Wind, session length, sunshine, and exertion also affect comfort; temperature alone does not describe sea conditions.

Sea Surface Temperature Over the Year

In the data collected for Tumon Bay, monthly averages range from about 29.4°C (84.9°F) in July to 29.7°C (85.5°F) in June.

Over the past 30 days, the average sea temperature in Tumon Bay has been 29.5°C.

Northern Hemisphere. Summer is generally June–August; winter is December–February.

Month	Min	Average	Max
June	29.0°C / 84.2°F	29.7°C / 85.5°F	30.6°C / 87.1°F
July	28.8°C / 83.8°F	29.4°C / 84.9°F	30.4°C / 86.7°F
August	29.3°C / 84.7°F	29.5°C / 85.2°F	30.1°C / 86.2°F

Profile calculated from 1748 hourly forecast records across 3 monthly periods. This is a growing archive, not a long-term climate normal.

Protected preserve with shallow reef and reef fish off the main beach strip.

The current sea surface temperature in Tumon Bay is 29.4°C. Over the last 30 days, the average has been 29.5°C.

The warmest monthly average in the Tumon Bay archive is June, at around 29.7°C (85.5°F).

The coldest monthly average in the archive is July, at around 29.4°C (84.9°F).

At 29.4°C, the water is usually comfortable for swimming and snorkeling.

See how today's sea temperature, wave height, wind, and tides combine into a detailed snorkeling score for Tumon Bay.