What to expect for water quality, rainfall, and ocean conditions
Dry conditions and calm seas make Waimea Bay an excellent swimming destination. Waimea River discharge is minimal. Water quality is good.
April marks the transition to summer conditions at Waimea Bay. North swells decrease significantly. The bay starts becoming swimmable on calm days. Water quality improves as Waimea River discharge decreases with less rain.
Winter brings massive north swells to Waimea Bay, some of the largest rideable waves on Earth. The bay is closed to swimming during big surf events. Powerful currents and shore break make the water extremely dangerous.
Moderate. The shoulder season between spring break and summer offers a good balance of pleasant weather and manageable crowds.
The Hawaii Department of Health recommends staying out of the ocean for at least 72 hours after heavy rain. In april, rainfall is less frequent but individual storms can still produce contaminated runoff.
When conditions are clear, Waimea 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.
When in doubt, don't go out. 🤙