The National Weather Service has issued a statewide Flood Watch for all Hawaiian Islands through Friday afternoon, April 10. A developing kona low west of the islands is pulling deep tropical moisture northward, creating conditions for heavy rain, thunderstorms, and flash flooding on every island.

If you are in Hawaiʻi right now or flying in this week, your trip can still go forward. But you need to stay flexible, check conditions before heading out each morning, and make smart decisions about outdoor activities. Here is what is happening and what to do about it.

A kona low — a slow-moving low-pressure system that develops west or southwest of the islands — is drawing tropical moisture across the entire state. Unlike trade-wind showers that hit windward coasts and pass quickly, kona systems produce widespread, prolonged rainfall that can affect every side of every island.

The heaviest rainfall is expected to develop late Wednesday night through Friday, moving from Kauaʻi to Oʻahu and then eastward across the state. The NWS warns of significant flooding from excessive rainfall and overflowing streams, with possible road closures, property damage in low-lying areas, and landslides in steep terrain.

Hana on Maui has already received 7 inches of rain in the current round, and Pahoa on the Big Island has seen 6 inches. More is coming.

Kauaʻi: Expected to get hit first as the system moves in from the west. North Shore and mountain areas are most vulnerable to flash flooding. The Kalalau Trail and Waimea Canyon roads may close on short notice. Check DLNR State Parks before heading out.

Oʻahu: The heaviest rain moves in Thursday. Urban flooding is the primary risk — Honolulu’s storm drains handle routine showers, not sustained downpours. The North Shore saw 13 inches in 12 hours during the March kona low. Avoid low-lying stream crossings, and stay off trails in the Koʻolau Range during active rainfall. The City is posting regular updates.

Maui: East Maui and the Road to Hana are the weak spots. Water over Hana Highway has already been reported near Hamoa. If you have a Hana drive planned for Thursday or Friday, postpone it. West Maui (Kaʻanapali, Lahaina) typically fares better during kona events, but is not immune. Check HDOT traffic alerts for highway closures.

Big Island: Hilo side will see the most rain. Flash flood warnings were issued and later canceled for parts of the island earlier this week. Hawaiʻi Volcanoes National Park remains open but conditions can change fast — check the NPS conditions page. Kona coast resorts tend to stay drier.

Check conditions every morning. Bookmark gohawaii.com/weatheralerts — the Hawaiʻi Visitors & Convention Bureau is updating it as conditions evolve. Also check NWS Honolulu for active warnings and watches.

Contact your airline. Check with your carrier for any schedule changes. Most airlines offer free rebooking during severe weather events. If you are mid-trip, confirm your return flight status.

Postpone exposed outdoor activities. Ridge hikes, waterfall chases, and the Road to Hana should wait until the Flood Watch lifts. Streams that look crossable can turn deadly in minutes during heavy rain. This is not the time for backcountry adventures.

Stay on resort-side. Hotel pools, spa days, restaurant hopping, shopping, and cultural activities are all solid rain-day options. Many of Hawaiʻi’s best experiences do not require sunshine — museum visits, food tours, and luaus run rain or shine.

Avoid flooded roads. Do not drive through standing water. Six inches of moving water can knock you off your feet. Twelve inches can carry a vehicle. If a road is flooded, turn around.

Sign up for emergency alerts. Hawaiʻi uses Wireless Emergency Alerts (WEA) for imminent threats. Your phone should receive them automatically as long as WEA is enabled in your settings.

Kona lows are not unusual in late winter and early spring. Hawaiʻi’s wet season runs roughly October through April, and kona systems are the mechanism that delivers the heaviest rainfall events. The March 2026 kona low was historically severe — multiple kona lows between March 10 and March 22 dropped over 46 inches on parts of Maui and 13 inches in 12 hours on Oʻahu’s North Shore.

This current system is expected to be less intense than March, but the islands are saturated. Ground that absorbed the March storms has less capacity to absorb more water, which means runoff happens faster and flash flooding triggers more easily. That is the main reason the NWS issued a statewide watch rather than targeted warnings.

By the weekend, the system is forecast to move away and trade winds should return. Conditions are expected to improve significantly by Saturday.

Tropical weather is part of what keeps these islands green. Conditions vary enormously by island and even by neighborhood — a downpour in Hilo does not mean it is raining in Kona, 90 miles away. The resorts, restaurants, cultural sites, and communities that make Hawaiʻi worth visiting are open and welcoming guests.

The Hawaiʻi Tourism Authority and HVCB have set up a dedicated weather alerts page with real-time conditions and visitor guidance. If you are deciding whether to cancel, check that page first. The answer is almost certainly: come to Hawaiʻi, stay flexible, and keep an eye on the forecast.

For rental cars on your trip, Discount Hawaii Car Rental often has the best rates — and having your own car gives you the flexibility to shift plans if one part of the island is getting hammered and another is dry.

• GoHawaii.com Weather Alerts — HVCB visitor conditions page
• NWS Honolulu Active Alerts — official watches, warnings, and advisories
• HDOT Weather Traffic Alerts — road closures statewide
• DLNR State Parks — park closure announcements
• Hawaiʻi Volcanoes NP Conditions
• HTA Travel Alerts