Mixed picture: Big Island stable, Maui improving, O'ahu worsening, Kaua'i worsening.
Per-island direction of change, based on the last 14 days of Hawaii DOH advisory data compared to the 14 days before, plus NOAA 7-day rainfall forecast at each island's tourist coast.
Stable · 100% of beach-days were clean in the last 14 days (0.0pp vs the 14 days before, when 100% were).
On 14 of the last 14 days, a majority of tracked Big Island beaches were advisory-free (vs 14/14 the two weeks prior).
Improving · 100% of beach-days were clean in the last 14 days (+57.1pp vs the 14 days before, when 43% were).
On 14 of the last 14 days, a majority of tracked Maui beaches were advisory-free (vs 6/14 the two weeks prior).
Worsening · 0% of beach-days were clean in the last 14 days (-32.1pp vs the 14 days before, when 32% were).
On 0 of the last 14 days, a majority of tracked O'ahu beaches were advisory-free (vs 6/14 the two weeks prior).
Worsening · 0% of beach-days were clean in the last 14 days (-57.1pp vs the 14 days before, when 57% were).
On 0 of the last 14 days, a majority of tracked Kaua'i beaches were advisory-free (vs 8/14 the two weeks prior).
As of 2026-04-23, Mixed picture: Big Island stable, Maui improving, O'ahu worsening, Kaua'i worsening. This page aggregates live Hawaii Department of Health advisory data across 31 tracked beaches and compares the last 14 days against the 14 days before to show the actual direction of change per island. Forward-looking outlook uses NOAA National Weather Service rainfall forecasts for the next 7 days at each island's primary tourist coast.
Seven days is too noisy — single storms dominate and testing schedules can create false trends. Thirty days captures pre-trip-window data that's less relevant to a planner deciding right now. Fourteen days is long enough for signal, short enough to be responsive to current storms, and gives us two comparable windows (last 14 vs prior 14) to measure actual direction of change.
Hawaii Brown Water Advisories follow rainfall by about 24-72 hours — upland rain drains through streams, which push runoff to the coast. If the next 7 days are forecast dry at the tourist coast, we expect trends to hold or improve. If rain is forecast, expect new advisory activity to follow. The outlook narrative combines the current trend direction with the rainfall forecast (dry / mild / wet) into one actionable sentence per island.
The trend data comes from the Hawaii Department of Health Clean Water Branch public API, which our pipeline polls daily. The 14-day window is the last 14 days of our 30-day per-beach tracking (31 beaches statewide). The weather forecast comes from NOAA's National Weather Service API (api.weather.gov) sampled at one leeward-coast point per island where trip planners actually go: Kohala Coast, South Maui, Honolulu South Shore, and Po'ipu. Both refresh daily.
No. This page measures water-quality DIRECTION of change — whether bacteria and Brown Water Advisory activity has been increasing or decreasing across an island. It is not a swim recommendation. Physical hazards (shore break, rip currents, surf, marine life) are independent of water quality and vary by beach. Always check the individual beach page for current DOH status and physical-hazard information before entering the water.