← Back to blog ← All beaches
TREND REPORT

Hawaii Water Quality — May 31, 2026

Maui water quality is worsening (-79pp in 14 days)

BIG ISLAND
+21pp improving
MAUI
-79pp worsening
OʻAHU
+14pp improving
KAUAʻI
+64pp improving

Maui ocean water quality worsened 79 percentage points over the last 14 days (100% clean two weeks ago vs. 21% clean now).

For a trip in the next week, prioritize islands with stronger structural protection (dry coasts, reef enclosure, no major streams). See cleanest Hawaiian island and BWA alternatives.

Where the islands stand today

Big Island

improving

Big Island is improving over the last 14 days (+21pp vs. the prior two weeks). 0 of our 7 tracked beaches on the island have active advisory days in the last 30 days. NOAA's 7-day forecast is dry, so the improving trend should continue. See the Big Island leaderboard for the beach-by-beach ranking.

Maui

worsening

Maui is worsening over the last 14 days (-79pp vs. the prior two weeks). 1 of our 6 tracked beaches on the island have active advisory days in the last 30 days. NOAA's 7-day forecast is mild — scattered showers possible but unlikely to drive new advisories. See the Maui leaderboard for the beach-by-beach ranking.

Oʻahu

improving

Oʻahu is improving over the last 14 days (+14pp vs. the prior two weeks). 1 of our 12 tracked beaches on the island have active advisory days in the last 30 days. NOAA's 7-day forecast is mild — scattered showers possible but unlikely to drive new advisories. See the Oʻahu leaderboard for the beach-by-beach ranking.

Kauaʻi

improving

Kauaʻi is improving over the last 14 days (+64pp vs. the prior two weeks). 6 of our 6 tracked beaches on the island have active advisory days in the last 30 days. NOAA's 7-day forecast is mild — scattered showers possible but unlikely to drive new advisories. See the Kauaʻi leaderboard for the beach-by-beach ranking.

NOAA 7-day forecast, per island tourist coast
  • Kohala Coast, Big Island: dry (max 16% chance of rain across next 7 days)
  • South Maui (Wailea / Kihei): mild (max 22% chance of rain across next 7 days)
  • South Shore O’ahu (Honolulu / Waikiki): mild (max 29% chance of rain across next 7 days)
  • Po’ipu, Kaua’i: mild (max 36% chance of rain across next 7 days)

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

Get the Daily Hawaii Water Quality Report

New report every day: trend per island, NOAA forecast, today's cleanest and most-advisoried beaches. Free — unsubscribe anytime.

Methodology: Statistics in this report come from our pipeline's aggregation of Hawaii DOH Clean Water Branch advisory data across 31 tracked beaches (last 14 days compared against the 14 days before). Forecast data from NOAA National Weather Service (api.weather.gov) sampled at each island's primary tourist coast. All numbers accurate as of publication. This report describes water-quality trends and forecast; it is not a swim recommendation. Physical hazards (shore break, rip currents, surf, marine life) are independent of water quality. Always check the individual beach page and local conditions before entering the water.