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Hidden Reef

Located near the entrance of Apra Harbor in Guam, United States, this beautiful reef is a hidden gem that is not typically explored by divers. Accessible only by boat, it offers a unique and undisturbed experience. The reef boasts an impressive variety of pristine corals, and its gradually sloping wall allows divers to reach a maximum depth of 23m. With visibility usually ranging from 20m, the underwater world comes to life, revealing incredible coral growth and thriving ecosystems.

Divers will be delighted by the presence of several large anemone beds and schools of colorful reef fish. The reef also showcases stunning stands of elephant ear sponges, adding to its allure. Whether you are a beginner, advanced, or expert diver, this captivating dive site offers something for everyone.

For those seeking an unforgettable underwater adventure, this secluded reef near Apra Harbor is a must-visit destination. Prepare to immerse yourself in the vibrant marine ecosystem while exploring the rich biodiversity that thrives beneath the crystal-clear waters. Don't miss out on this exceptional diving experience accessible exclusively by boat.

Diving Conditions Score for Hidden Reef

6.1
Above Average

Decent conditions, proceed with caution.
The score is based on a calculation of the current weather and sea conditions.

Dive Site Overview for Hidden Reef

Depth

23m

Visibility

20m

Experience Level

beginner
advanced
expert

Weather Conditions for Hidden Reef

Wave Height

1.44m

Wind Speed

20.1 m/s

Water Temp

29°C

Visibility

4.08km

Cloud Cover

73%

Wave Period

8.7s

Air Temperature

29.7°C

Precipitation

0.6 mm

Detailed 7-Day Diving Forecast for Hidden Reef
Alpha

Dive Score Chart for Hidden Reef

Best time to dive: 10:00 with score 6.558443859649122/10. Water conditions: Waves 1.26m, Wind 16.5 m/s.Best night dive time: 4:00 with score 5.9718/10.

Chart showing hourly dive conditions including wave height, wind speed, water temperature, and visibility throughout the day.

Sunrise at Hidden Reef: 06:00
Sunset at Hidden Reef: 18:00

Optimal diving conditions at Hidden Reef are affected by daylight hours. Sunrise occurs at 06:00 and sunset at 18:00, which impacts visibility and water temperature for scuba diving and snorkeling.

🌞
Best Overall
10:00

Score: 6.6/10
Waves: 1.26m (8.55s), Wind: 16.5 m/s

🌙
Best Night
4:00

Score: 6.0/10
Waves: 1.4m, Wind: 19.4 m/s

Seasonal Analysis for Hidden Reef
Alpha

Historical patterns and best seasons for diving at Hidden Reef

The dive score combines all factors to rate overall diving conditions throughout the year. Higher scores indicate better diving conditions.

Monthly Dive Score Analysis - Seasonal Diving Conditions

Higher values indicate better diving conditions

Seasonal DiveScore Chart

This chart displays monthly diveScore data throughout the year, showing seasonal patterns. The data is presented as a bar chart with an overlaid line graph.Dive scores range from 1 to 10, with 10 being optimal conditions.

Higher values indicate better diving conditions

Best Season for Hidden Reef

Winter

Avg. Score: 9.4/10

Winter offers the best overall diving conditions with calmer seas and better visibility, despite cooler temperatures.

Best Months for Hidden Reef

January
Score: 9.5
February
Score: 9.4
November
Score: 9.4

Ideal Conditions for Hidden Reef

Water Temp

Thermometer Emoji

27.6°C / 81.7°F

May

Visibility

Telescope Emoji

11.2m / 36.7ft

November

Wave Height

Wave Emoji

1.4m / 4.6ft

September

Wave Period

Wave Emoji

8.0s

January

Seasonal Insights for Hidden Reef

Hidden Reef shows typical northern hemisphere patterns with May being the warmest month (27.6°C) and January the coldest (22.7°C). The calmest conditions typically occur in September with average wave heights of 1.4m and wave periods of 8.0s. The most comfortable wave conditions are in September with a low wave steepness ratio, creating gentler swells. January offers the longest wave periods (8.0s), creating more comfortable and predictable conditions for boat entries and exits. Ocean currents are slowest in January (0.5m/s) and strongest in January (0.5m/s). February is usually the driest month with 1.0mm of precipitation. For beginners, the best time to visit would be during September to November, when ocean conditions are calmer with long-period waves and currents are typically weaker. Experienced divers might enjoy the challenges and potentially better visibility during the shoulder seasons, with moderate currents that can improve marine life encounters.

Scoring Legend:
9-10 (Excellent)
7-8 (Good)
5-6 (Average)
3-4 (Poor)
1-2 (Dangerous)

Last updated: 1 min. ago - Jul 13, 2026

Note: This dive site is not a verified dive site. Please dive with caution. This dive site might have incorrect information by the community.

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