Hilo

Today: Mostly cloudy with isolated showers and thunderstorms. Locally heavy rainfall possible. Highs 79 to 84 near the shore to 65 to 71 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Tonight: Cloudy with scattered showers and slight chance of thunderstorms. Locally heavy rainfall possible. Lows 60 to 71 near the shore to 54 to 60 at 4000 feet. Light winds. Chance of rain 50 percent.

Sunday: Occasional showers and slight chance of thunderstorms. Locally heavy rainfall possible. Highs around 79 near the shore to around 64 at 4000 feet. Light winds. Chance of rain near 100 percent.

Kona

Today: Mostly cloudy with showers likely and isolated thunderstorms. Locally heavy rainfall possible. Highs 81 to 86 near the shore to around 68 near 5000 feet. South winds up to 10 mph. Chance of rain 70 percent.

Tonight: Cloudy with scattered showers and slight chance of thunderstorms. Locally heavy rainfall possible. Lows around 72 near the shore to around 53 near 5000 feet. Light winds. Chance of rain 50 percent.

Sunday: Occasional showers and slight chance of thunderstorms. Locally heavy rainfall possible. Highs around 83 near the shore to around 64 near 5000 feet. Light winds. Chance of rain near 100 percent.

Waimea

Today: Mostly cloudy with scattered showers and isolated thunderstorms. Locally heavy rainfall possible. Highs around 79 near the shore to 70 to 76 near 3000 feet. Light winds. Chance of rain 50 percent.

Tonight: Cloudy with showers likely and slight chance of thunderstorms. Locally heavy rainfall possible. Lows 62 to 71 near the shore to 56 to 63 near 3000 feet. Light winds. Chance of rain 70 percent.

Sunday: Cloudy with occasional showers and slight chance of thunderstorms. Locally heavy rainfall possible. Highs around 78 near the shore to 67 to 73 near 3000 feet. Light winds. Chance of rain 90 percent.

Kohala

Today: Mostly cloudy with scattered showers and isolated thunderstorms. Locally heavy rainfall possible. Highs around 79 near the shore to 70 to 76 near 3000 feet. Light winds. Chance of rain 50 percent.

Tonight: Cloudy with showers likely and slight chance of thunderstorms. Locally heavy rainfall possible. Lows 62 to 71 near the shore to 56 to 63 near 3000 feet. Light winds. Chance of rain 70 percent.

Sunday: Cloudy with occasional showers and slight chance of thunderstorms. Locally heavy rainfall possible. Highs around 78 near the shore to 67 to 73 near 3000 feet. Light winds. Chance of rain 90 percent.

South Big Island

Today: Mostly cloudy with showers likely and isolated thunderstorms. Locally heavy rainfall possible. Highs around 83 near the shore to around 67 near 5000 feet. Southeast winds up to 10 mph. Chance of rain 60 percent.

Tonight: Cloudy with scattered showers and slight chance of thunderstorms. Locally heavy rainfall possible. Lows around 75 near the shore to around 57 near 5000 feet. Light winds. Chance of rain 50 percent.

Sunday: Occasional showers and slight chance of thunderstorms. Locally heavy rainfall possible. Highs around 82 near the shore to around 65 near 5000 feet. East winds up to 10 mph in the morning becoming light. Chance of rain near 100 percent.

Puna

Today: Mostly cloudy with isolated showers and thunderstorms. Locally heavy rainfall possible. Highs 79 to 84 near the shore to 65 to 71 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Tonight: Cloudy with scattered showers and slight chance of thunderstorms. Locally heavy rainfall possible. Lows 60 to 71 near the shore to 54 to 60 at 4000 feet. Light winds. Chance of rain 50 percent.

Sunday: Occasional showers and slight chance of thunderstorms. Locally heavy rainfall possible. Highs around 79 near the shore to around 64 at 4000 feet. Light winds. Chance of rain near 100 percent.

Waikoloa

Today: Mostly cloudy. Scattered showers and isolated thunderstorms early in the morning, then showers and isolated thunderstorms in the late morning and afternoon. Locally heavy rainfall possible. Highs 81 to 87 near the shore to around 68 above 4000 feet. Light winds. Chance of rain 80 percent.

Tonight: Cloudy with scattered showers and slight chance of thunderstorms. Locally heavy rainfall possible. Lows around 72 near the shore to 53 to 58 above 4000 feet. Light winds. Chance of rain 50 percent.

Sunday: Cloudy with occasional showers and slight chance of thunderstorms. Locally heavy rainfall possible. Highs 79 to 84 near the shore to 63 to 68 above 4000 feet. Light winds. Chance of rain 90 percent.

Detailed Forecast

Synopsis

Our kona storm will remain with us through Sunday for most islands, but the threat of flooding has become low enough for Kauai and Niihau that the flood watch has been cancelled there. For the remainder of the state, expect periods of showers, some heavy, to continue tonight and Sunday. As the system moves off to the east Sunday night and Monday, trades will return from west to east Monday into Monday night and then continue through the end of the week. Windward showers will be scattered to numerous Monday into Monday night, then decrease for the remainder of the week.

Short term update

Issued at 812 PM HST Sat Mar 21 2026
The forecast remains largely on track, with showers and isolated thunderstorms continuing over the smaller islands, moving eastward. Heaviest of showers are currently over Maui County, specifically around the Lanai which has seen 1 to 2 inches of precipitation in the last 6 hours as of 7:30 HST. Otherwise, isolated showers continue to develop southwest of the Hawaiian Islands. The Flood Watch remains in effect for Oahu, Maui County, and Big Island at this time as a result. Additionally, the Winter Storm Warning remains in effect through 6 PM Sunday for the Big Island summits. Outside of the showers, winds remain light across the region, therefore, no amendments were made to the forecast at this time.

Prev discussion

Issued at 335 PM HST Sat Mar 21 2026
Radar shows showers and isolated thunderstorms moving northeast over parts of the state. The largest area of showers as of 3 PM HST was over Maui County, with showers also over parts of the Big Island (mainly N and S Hilo).
The upper level trough that has brought us this kona storm continues to drift slowly east as it evolves, with shortwaves moving through the trough. Today, the associated surface low has started to move northeast away from the state. This is the beginning of the end of this system. However, it will remain close enough for a continued threat of flash flooding from Oahu east through the Big Island through Sunday afternoon. Flood warnings remain in effect this afternoon for much of Maui County. Periods of showers and isolated thunderstorms are still expected tonight and Sunday. Moisture levels remain high and cold temperatures aloft will bring continued instability. Therefore, rainfall rates have the potential to be high.
Sunday night and Monday, the upper trough will weaken and slowly slide across and east of the state. At the same time, the surface low will move significantly farther away. This will allow a high pressure center to build in to the north of the state, and trade winds will return Monday to the western islands, and Monday night to the eastern islands. Low level moisture left over from the kona storm will result in scattered windward showers on western and central islands Monday, with numerous showers on windward Big Island into Monday night. From Tuesday through the end of the week, expect typical trade wind weather, with isolated to scattered showers windward and very few if any showers on the leeward side.

Aviation

Issued at 812 PM HST Sat Mar 21 2026
Bands of showers and embedded thunderstorms continue to move over Maui County and potentially may move east over the Big Island. The ongoing kona low will support further rain bands, mainly across Oahu and Maui County, through the forecast period. Rainfall may spread to Kauai, though confidence is lower for the western end of the state. Winds will remain primarily out of the south to southwest. Expect widespread MVFR conditions over Maui County through the forecast period, with locally LIFR conditions under showers.
AIRMET Sierra is in effect for Molokai, Maui, and Lanai due to widespread low ceilings and showers and is expected to continue overnight. AIRMET Sierra is also in effect for Oahu due to mountain obscuration and will continue to monitor this through the night.
AIRMET Tango remains in effect for moderate turbulence downwind of terrain for Oahu and Maui County below 070 from gusty south to southwest winds associated with the kona low. However, winds are showing some signs of weakening, so we may be able to cancel this AIRMET later tonight or Sunday.
Light icing in layer 140-FL260 will also persist, mainly over the central portion of the state where the thick high clouds continue to stream over from the southwest.

Marine

Issued at 335 PM HST Sat Mar 21 2026
Bands of heavy showers and a few thunderstorms will continue to move over portions of the coastal waters, especially the central and eastern waters, as a kona low continues to impact the state. Prevailing southerly moderate to locally breezy winds continue across portions of the area as well. The low will lift farther north on Sunday, allowing light to moderate northerly winds to develop around Kauai, which will then veer to northeast and spread southward. Additionally, due to wave heights around Niihau, Kauai, and Oahu near 10 feet, a Small Craft Advisory remains in effect for those waters until 6AM Sunday.
A northerly swell is peaking today, and is producing borderline advisory-level surf for north facing shores of Niihau, Kauai, and Oahu as of this afternoon. This will continue into the evening hours before slowly declining overnight. As such, a High Surf Advisory (HSA) remains in effect for north facing shores for Niihau, Kauai, and Oahu until 6AM Sunday. Additionally, a slight bump is expected from a small, building west-northwest swell that will peak Sunday.
A small south swell is slowly declining and will continue to trend down through the rest of the weekend into early next week. Smaller surf is expected along south facing shores through the remainder of the week. Surf along east-facing shores remains elevated due to wrap from the north swell, and will be near HSA thresholds. This swell will slowly diminish through the rest of the weekend as well.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Sunday for Kauai East, Kauai North, Koolau Windward, Niihau, Oahu North Shore, Olomana.
Flood Watch through Sunday afternoon for Big Island East, Big Island Interior, Big Island North, Big Island South, Big Island Southeast, Central Oahu, East Honolulu, Ewa Plain, Haleakala Summit, Honolulu Metro, Kahoolawe, Kipahulu, Kohala, Kona, Koolau Leeward, Koolau Windward, Lanai Leeward, Lanai Mauka, Lanai South, Lanai Windward, Maui Central Valley North, Maui Central Valley South, Maui Leeward West, Maui Windward West, Molokai Leeward South, Molokai North, Molokai Southeast, Molokai West, Molokai Windward, Oahu North Shore, Olomana, South Haleakala, South Maui/Upcountry, Waianae Coast, Waianae Mountains, Windward Haleakala.
Winter Storm Warning until 6 PM HST Sunday for Big Island Summits.
Small Craft Advisory until 6 AM HST Sunday for Kaiwi Channel, Kauai Channel, Kauai Leeward Waters, Kauai Northwest Waters, Kauai Windward Waters, Oahu Windward Waters.

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Data Courtesy of NOAA.gov