West Kaua’i

Tonight: Cloudy. Occasional showers and isolated thunderstorms in the evening, then occasional showers after midnight. Locally heavy rainfall possible in the evening. Lows around 73 near the shore to around 65 above 3000 feet. Light winds becoming northeast up to 15 mph after midnight. Chance of rain 80 percent.

Sunday: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 84 to 90 near the shore to around 75 above 3000 feet. Northeast winds up to 20 mph. Chance of rain 50 percent.

Sunday Night: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 71 near the shore to around 62 above 3000 feet. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

South Kaua’i

Tonight: Cloudy. Occasional showers and isolated thunderstorms in the evening, then numerous showers after midnight. Locally heavy rainfall possible in the evening. Lows 71 to 76. Northeast winds 10 to 15 mph. Chance of rain 80 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 79 to 89. Northeast winds 10 to 25 mph increasing to 20 to 25 mph in the afternoon. Chance of rain 50 percent.

Sunday Night: Breezy. Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 68 to 75. Northeast winds 15 to 25 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Cloudy and breezy. Occasional showers and isolated thunderstorms in the evening, then occasional showers after midnight. Locally heavy rainfall possible in the evening. Lows around 69 in the valleys to around 62 above 4000 feet. East winds 10 to 15 mph shifting to the northeast up to 20 mph after midnight. Chance of rain 90 percent.

Sunday: Mostly cloudy. Windy. Occasional showers in the morning, then numerous showers in the afternoon. Highs 72 to 80 in the valleys to around 66 above 4000 feet. Northeast winds up to 25 mph increasing to 15 to 30 mph in the afternoon. Chance of rain 90 percent.

Sunday Night: Mostly cloudy. Windy. Numerous showers in the evening, then scattered showers after midnight. Lows 63 to 68 in the valleys to around 59 above 4000 feet. Northeast winds 15 to 30 mph with gusts to 50 mph. Chance of rain 70 percent.

North Kaua’i

Tonight: Mostly cloudy. Occasional showers and isolated thunderstorms in the evening, then numerous showers after midnight. Locally heavy rainfall possible in the evening. Lows 65 to 75. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 80 percent.

Sunday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 69 to 84. Northeast winds up to 25 mph increasing to 15 to 25 mph in the afternoon. Chance of rain 70 percent.

Sunday Night: Breezy. Mostly cloudy with scattered showers. Lows 62 to 73. Northeast winds 10 to 25 mph. Chance of rain 50 percent.

East Kaua’i

Tonight: Cloudy. Occasional showers and isolated thunderstorms in the evening, then numerous showers after midnight. Locally heavy rainfall possible in the evening. Lows 67 to 76. East winds around 10 mph shifting to the north after midnight. Chance of rain 90 percent.

Sunday: Breezy. Partly sunny with scattered showers. Highs 76 to 84. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Sunday Night: Breezy. Mostly cloudy with scattered showers. Lows 64 to 75. Northeast winds 10 to 25 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

An approaching disturbance aloft combined with ample moisture and a surface trough moving over the western end of the state have triggered heavy showers and isolated thunderstorms over Kauai and Niihau and may impact Oahu overnight. The tail end of a front will move down the island chain late Sunday through Monday, bringing breezy northeasterly trades and drier air in its wake. Breezy easterly trades will bring periods of windward and mauka showers through the rest of the week.

Short term update

Heavy rain continues over the Ko'olau range, especially from around Punalu'u southeastward. Most of the heavy rain has ended over Kauai, but flooding continues as runoff hasn't ended yet. A large area of showers, some quite strong, is moving east through the Kauai Channel. This area should reach Oahu in the next few hours, but at this time we don't know if the heavier showers will hit the island or stay south. Some high resolution guidance shows it will, while some shows it remaining south. No changes will be made to the forecast at this time.

Prev discussion

Issued at 404 PM HST Sat Oct 31 2026 Trade wind showers anchored along the eastern slopes of Kauais mountains have persistently produced heavy rain through the day in a moist and unstable environment, as evidenced in this afternoons upper air sounding at Lihue. Rainfall rates and gage stream reports prompted the issuance of a Flash Flood Warning for the entire island, with the main trouble spots including the Hanalei Bridge along the Kuhio Highway and the South Fork of the Wailua River. This warning remains in effect through 5:45 PM this evening and will likely be extended. Heavy showers and isolated thunderstorms firing along a surface trough edging over Niihau and Kauai this afternoon will likely maintain the flood threat for the next couple of hours. Showers have also been persistent across Oahu through the day, but rainfall rates and stream gage responses have been unimpressive so far. However, the heavy showers and isolated thunderstorms currently over Kauai may impact Oahu overnight into Sunday morning as an upper level trough helps drive them eastward in advance of an approaching front, depending on how well the surface trough and the various outflow boundaries hold together.
The next pattern change arrives late Sunday into Sunday night as the tail end of a shallow front pushes down the island chain before dissipating. While this boundary will deliver an uptick in showers to windward and north-facing slopes, its primary impact will be the development of breezy and gusty northeast trade winds spreading from west to east. Deep high pressure building behind the front will usher in a drier, more stable air mass. This will lead to a break from the muggy conditions weve been experiencing this past week as dew points are expected to drop into the lower 60s on Monday and Tuesday.
Breezy and stable easterly trades will persist through much of the workweek as the northern high becomes elongated in response to broad low pressure system tracking across the North Pacific. Dew points will gradually rebound closer to seasonal norms by midweek. While rainfall will remain largely focused along windward slopes with only brief leeward drift, a minor uptick in shower coverage appears possible around midweek as trade moisture interacts with added instability from a passing weak mid-level shortwave trough.
Heading into next weekend, forecast attention shifts back to the tropics. While significant spread exists regarding timing and track details, model guidance continues to hint at potential tropical cyclone development far southeast of the state late in the week, with the system potentially nearing or passing south of the islands over the weekend. While background trades look to hold, questions remain concerning their ultimate strength and how much deep moisture is drawn into the region. The National Hurricane Center continues to monitor this area, maintaining a medium (40 percent) chance of tropical cyclone formation over the next 7 days.

Aviation

Scattered showers currently between Kauai and Oahu will start to push towards PHNL and PHJR (and the rest of Oahu) over the next couple of hours. Persistent MVFR and some IFR ceilings and visibilities are possible in the heavier showers. If these hold together, they could affect Molokai, Lanai, and Maui by morning.
AIRMET Sierra remains in effect for IFR conditions on Kauai which may need to be extended into Oahu. AIRMET Sierra is also in effect for mountain obscuration on Oahu and windward areas of the Big Island due to low ceilings and reduced visibility in showers.

Marine

Issued at 404 PM HST Sat Oct 31 2026 A High Surf Advisory has been posted for north and west facing shores due to an incoming northwest swell. Additionally, a Small Craft Advisory has been issued for all coastal waters due to increasing winds and seas.
A trough to the northwest of Kauai will sink southward overnight, allowing high pressure to the north to strengthen winds behind the trough over the region. An incoming north-northwest (330 degrees) swell will push seas in excess of 10 feet for exposed waters, and the strengthening winds will bring SCA level winds to additional areas. Moderate to fresh northeast trades are expected to continue through much of the week.
The forerunners from the new moderate, long-period northwest swell are expected to arrive in the next couple of hours, with the swell building quickly overnight. By Sunday, advisory level surf is expected for north and west facing shores, which is expected to continue into Monday. The swell may shift to a slightly more northerly direction on Monday before declining on Tuesday. Depending on the exact direction, a Marine Weather Statement may be issued for potential harbor surges at Kahului and Hilo during that time. Another advisory level northwest swell is possible Thursday into Friday.
The current moderate, medium period south swell will gradually decline through the weekend. Surf above seasonal average returns to seasonal average on Sunday as the south swell energy fades. During the first half of next week, south shore surf will return to below seasonal averages.
East-facing shores will see an increase in trade wind swell as northeast winds return on Sunday. Surf along east-facing shores will increase through Monday night and conditions will be choppy as trades sustain through much of the week.

Fire weather

Issued at 404 PM HST Sat Oct 31 2026 The anomalously wet conditions during the past few months and the rainfall from the past few days has kept the Keetch-Byram Drought Index (KBDI) below 500 across nearly all of the state. Fire weather concerns will be low through early Sunday as trade winds remain light and humidity elevated. Breezy and much drier trade winds will develop by Monday, but since KBDI will remain suppressed, fire weather conditions will be moderate.

HFO Watches/Warnings/Advisories

High Surf Advisory from 6 AM Sunday to 6 PM HST Monday for Kauai East, Kauai North, Kauai Southwest, Koolau Windward, Maui Central Valley North, Maui Windward West, Molokai North, Molokai Windward, Niihau, Oahu North Shore, Waianae Coast, Windward Haleakala.
Small Craft Advisory from 6 AM Sunday to 6 PM HST Monday for Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters, Big Island Windward Waters, Kaiwi Channel, Kauai Channel, Kauai Leeward Waters, Kauai Northwest Waters, Kauai Windward Waters, Maalaea Bay, Maui County Leeward Waters, Maui County Windward Waters, Oahu Leeward Waters, Oahu Windward Waters, Pailolo Channel.

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Data Courtesy of NOAA.gov