What to expect for water quality, rainfall, and ocean conditions
Hanalei Bay has very high bacteria risk during peak wet season. Four rivers carry contaminated runoff from a watershed with 360+ cesspools. The bay has been on the EPA impaired waters list since 2004. Avoid swimming near river mouths.
February continues extreme rainfall on Kauai's north shore. Hanalei Bay receives massive runoff from all four river systems. The 360+ cesspools in the Hanalei watershed become saturated during extended rain, increasing sewage leaching into groundwater and rivers flowing to the bay.
Winter north swells transform Hanalei Bay into a powerful surf zone. Waves regularly exceed 10-15 feet. The bay is extremely dangerous for swimming during big swell events. Strong currents develop near the pier and river mouths.
Extremely high. December through February is peak tourist season driven by holiday travel and mainland winter escapes. Book accommodations and tours well in advance.
The Hawaii Department of Health recommends staying out of the ocean for at least 72 hours after heavy rain. In february, this is especially important as wet-season storms can produce heavy rainfall and significant runoff.
When conditions are clear, Hanalei Bay has excellent ocean activities. Check the water quality above, then book with confidence.
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Safe to Swim Hawaii provides water quality information based on publicly available DOH data and seasonal patterns. This is not medical or safety advice. Always check current conditions, obey posted signs, and use your own judgment before entering the ocean. Privacy Policy
⚠️ Important Disclaimer
Safe to Swim Hawaii is an independent passion project — not affiliated with the Hawaii Department of Health or any government agency. Water quality 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 water quality conditions with the Hawaii DOH Clean Water Branch before entering the water.
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