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ADVISORY HISTORY

Hawaii Water Quality — September 18, 2026

Waimea Bay: no advisory recorded for September 17 in the daily history

BIG ISLAND
Mostly advisory-affected, stable (0% of days without an island advisory)
MAUI
-21pp worsening (36% of days without an island advisory)
OʻAHU
Mostly advisory-affected, stable (0% of days without an island advisory)
KAUAʻI
Mostly advisory-affected, stable (0% of days without an island advisory)

The daily history shows 10 tracked beaches with a recorded advisory on September 16, 2026 and no recorded advisory on September 17, 2026: Ala Moana Beach Park, Banzai Pipeline, Hanakaʻoʻo Beach Park, Hanauma Bay, Kailua Beach Park, Lanikai Beach, Sandy Beach, Sunset Beach, Turtle Bay Beach, Waimea Bay.

These are complete calendar days; a notice counts through its cancellation date. This comparison does not establish when a notice changed, current water quality, or conditions elsewhere on the island. Check the linked beach page and current DOH notices before entering the water. A historical change does not establish swimming safety or start a waiting-period countdown.

Where the islands stand today

Big Island

mostly advisory-affected

Big Island has remained mostly advisory-affected across both 14-day island-wide advisory-day windows (0% of days had no DOH advisory anywhere on the island in the latest window). All 7 of our tracked beaches on the island recorded one or more advisory days in that 30-day history window. NOAA's 7-day rainfall signal is mild. Rainfall probability does not predict whether DOH will issue or lift an advisory. See the Big Island leaderboard for the beach-by-beach ranking.

Maui

worsening

Maui is worsening over the last 14 days (-21pp vs. the prior two weeks). All 6 of our tracked beaches on the island recorded one or more advisory days in that 30-day history window. NOAA's 7-day rainfall signal is dry. A dry forecast does not establish current water quality or mean an advisory has cleared. See the Maui leaderboard for the beach-by-beach ranking.

Oʻahu

mostly advisory-affected

Oʻahu has remained mostly advisory-affected across both 14-day island-wide advisory-day windows (0% of days had no DOH advisory anywhere on the island in the latest window). All 12 of our tracked beaches on the island recorded one or more advisory days in that 30-day history window. NOAA's 7-day rainfall signal is mild. Rainfall probability does not predict whether DOH will issue or lift an advisory. See the Oʻahu leaderboard for the beach-by-beach ranking.

Kauaʻi

mostly advisory-affected

Kauaʻi has remained mostly advisory-affected across both 14-day island-wide advisory-day windows (0% of days had no DOH advisory anywhere on the island in the latest window). All 6 of our tracked beaches on the island recorded one or more advisory days in that 30-day history window. NOAA's 7-day rainfall signal is wet (peak 56% chance of rain). Rain can increase runoff risk; check current DOH advisories and local conditions. See the Kauaʻi leaderboard for the beach-by-beach ranking.

Historical advisory-free leaders (last 30 days)

These counts describe the recorded history. Check each beach's current status for active DOH advisories.

Hoʻokipa Beach Park
24/30 days advisory-free
Check current status →
Kaʻanapali Beach
24/30 days advisory-free
Check current status →
Keawakapu Beach
24/30 days advisory-free
Check current status →
NOAA 7-day forecast, per island tourist coast
  • Kohala Coast, Big Island: mild (peak 25%, average 15% chance of rain across the forecast periods)
  • South Maui (Wailea / Kihei): dry (peak 17%, average 9% chance of rain across the forecast periods)
  • South Shore O’ahu (Honolulu / Waikiki): mild (peak 38%, average 29% chance of rain across the forecast periods)
  • Po’ipu, Kaua’i: wet (peak 56%, average 40% chance of rain across the forecast periods)

For the always-live per-island outlook, see our Hawaii Water Quality Forecast, which regenerates daily from NOAA + DOH data.

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Methodology: The island trend uses Hawaii DOH island-wide advisory-day history where available: a day counts as advisory-free only when no DOH advisory was recorded anywhere on that island. If island history is unavailable, the generator labels its tracked-beach-fraction fallback explicitly. The separate beach list summarizes 31 tracked beach histories. Forecast data comes from NOAA National Weather Service (api.weather.gov) at each island's primary tourist coast. This report is not a swim recommendation; always check the individual beach page and current local conditions before entering the water.