What to expect for water quality, rainfall, and ocean conditions
Even during the transition to wet season, Kalapaki's proximity to the always-contaminated Nawiliwili Stream creates significant bacteria risk. The harbor adds to contamination. Water quality varies widely with recent rainfall.
October marks the return of significant rainfall to east Kauai at 4-5 inches. Nawiliwili Stream discharge increases sharply and Kalapaki water quality deteriorates quickly after rain events.
Winter north swells wrap into Nawiliwili Bay, creating surfable waves at Kalapaki. The inner bay stays calmer but winter surf can make the outer beach areas rough. Water temperature is around 75-77°F.
Moderate to low. Fall shoulder season offers fewer tourists while conditions remain good. This is one of the best value periods for visiting Hawaii.
The Hawaii Department of Health recommends staying out of the ocean for at least 72 hours after heavy rain. In october, this is especially important as wet-season storms can produce heavy rainfall and significant runoff.
When conditions are clear, Kalapaki Beach 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. 🤙