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BIG ISLAND · KOHALA COAST

Hapuna Beach Water Quality

Big Island's best white sand — summer vs. winter conditions & water clarity

📍 Kohala Coast, South Kohala, Hawaiʻi Island

Checking live advisories…
If It Looks Brown, Don't Swim
Hapuna is dry, but the rare Kona storm can bring rain and runoff. Never enter the ocean when water appears brown or murky. Wait at least 72 hours after any significant rain event.
Learn more about brown water advisories →
Historical Bacteria Risk
⚠ Historical rating — based on long-term testing data, not current conditions.
Low Risk 1 / 5

Hapuna Beach sits on the Big Island's Kohala Coast, one of the driest stretches of coastline in the entire Hawaiian Islands. Annual rainfall here averages under 10 inches — compare that to Hilo's 130+ inches per year. Very low rainfall means very low bacteria risk from runoff.

The beach also has excellent open-ocean flushing with no significant streams or storm drains nearby. DOH testing history at Hapuna has been consistently clean. The primary hazards here are physical — shore break and currents during large swells — not bacteria.

Based on: DOH monitoring history, Kohala Coast arid climate, no nearby stream inputs, strong open-ocean flushing

Seasonal Guide

Summer vs. Winter at Hapuna

SUMMER (May – September)

The classic Hapuna experience. Wide white sand beach, calm to moderate swells, excellent visibility. South swells can occasionally kick up shore break. Water temperature 78–82°F. Arrive early — the parking lot fills by 9am on weekends. Snorkeling is best at the rocky south end of the beach.

WINTER (October – April)

North swells arrive. Hapuna can go from calm to dangerous quickly. On big swell days, shore break pounds the steep beach face and rip currents form along the edges. Lifeguards may close the beach. Always check surf forecasts before visiting in winter. Water temperature drops to 74–77°F.

⚠️ The 72-Hour Rain Rule

The Department of Health recommends staying out of the ocean for at least 72 hours after heavy rain. While Hapuna's dry climate makes this rarely necessary, Kona storms can bring brief but intense rainfall. After any rain event, check the water visually before entering.

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⚠️ Important Disclaimer

Safe to Swim Hawaii is an independent passion project — not affiliated with the Hawaii Department of Health or any government agency. Ratings are estimates based on publicly available testing data and geographic analysis. They are not real-time measurements and may not reflect current conditions.

Always verify current conditions with the Hawaii Department of Health Clean Water Branch before entering the water.

When in doubt, don't go out. 🤙

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