West Kaua’i

Rest Of Tonight: Cloudy with numerous showers. Lows around 73 near the shore to around 63 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 70 percent.

Monday: Partly sunny with isolated showers. Highs around 87 near the shore to around 76 above 3000 feet. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 20 percent.

Monday Night: Partly cloudy with isolated showers. Lows around 72 near the shore to around 61 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

South Kaua’i

Rest Of Tonight: Cloudy with numerous showers. Lows around 73. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Monday: Mostly cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 88. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Monday Night: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows around 72. Northeast winds 10 to 15 mph. Chance of rain 60 percent.

Kaua’i Mountains

Rest Of Tonight: Cloudy with numerous showers. Lows 64 to 71 in the valleys to around 60 above 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Monday: Mostly cloudy with scattered showers. Highs 74 to 82 in the valleys to around 66 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Monday Night: Mostly cloudy with numerous showers. Lows 63 to 70 in the valleys to around 59 above 4000 feet. Northeast winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 70 percent.

North Kaua’i

Rest Of Tonight: Cloudy with numerous showers. Lows 66 to 74. Southeast winds up to 10 mph. Chance of rain 70 percent.

Monday: Mostly cloudy with scattered showers. Highs 76 to 86. East winds up to 10 mph. Chance of rain 40 percent.

Monday Night: Mostly cloudy with numerous showers. Lows 65 to 72. East winds around 10 mph. Chance of rain 70 percent.

East Kaua’i

Rest Of Tonight: Cloudy with numerous showers. Lows 65 to 77. Northeast winds around 10 mph. Chance of rain 70 percent.

Monday: Mostly cloudy with scattered showers. Highs 73 to 85. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Monday Night: Mostly cloudy with numerous showers. Lows 64 to 75. Northeast winds around 10 mph. Chance of rain 70 percent.

Detailed Forecast

Update

An update was made to the pop/sky forecast due to the showers across the western side of the state. Showers some heavy at times continue to move northward across Kauai and Oahu. Flooding rain is not anticipated at this time. The rest of the forecast remains on track. The next update will be at 3am HST unless needed sooner.

Synopsis

Trades will be here for at least the next 6 days, but will be weaker than the past few days. An upper level low/trough will help bring increased instability to the western end of the state, enhancing the chance for stronger showers through Tuesday. We expect thunderstorms to remain offshore.

Prev discussion

/ISSUED 351 PM HST Sun Oct 26 2025/
.DISCUSSION…
Satellite and radar show a large area of showers associated with an extensive cloud shield moving generally south to north. Rainfall amounts have been light, with just a few hundredths except on windward parts of the Big Island. There, several tenths have fallen. We expect showers to continue into the evening, with mostly light amounts, mainly across the western part of the state.
An upper level low 300-400 miles to our west has helped keep thunderstorms going, but so far they have been well offshore. This low will move NE through Monday night and weaken into a trough. It will then become nearly stationary over the state, bringing enhanced instability to the region. There is a slight chance for thunderstorms over/near Kauai and Niihau over the next couple of days due to the cold air aloft associated with this trough. Models also indicate enough instability developing over the Kona side of the Big Island Wednesday afternoon to warrant a mention of thunderstorms.
Wednesday, the trough will “pinch off” and form a new closed low to our southwest due to the influence of an upper ridge asserting itself eastward around 30 N. The low will move SW, away from the state. At the same time, a large central Pacific trough will move down the east side of the ridge, and may even push a boundary into or through the area late next weekend. Models have yet to come into agreement on the evolution of this system, and at this time range, that's to be expected.
At the surface, a series of high pressure centers to our north will move from west to east, keeping us in a trade wind pattern. Wind speeds will decrease slightly tomorrow compared to today, then generally hold at that level through the coming week. Windward and mauka showers will be favored, with some limited spillover to leeward sides.

Aviation

High pressure to the northeast will generate moderate to breezy trade winds tonight. Trade winds will then gradually decrease through the week as a front far to the north weakens the high pressure. Showers from low clouds on the trade winds will mostly focus over windward and mountain areas, however a few brief light showers from mid and high level clouds are possible anywhere. Low ceilings and MVFR conds are possible in any heavier showers, especially for windward Big Island, otherwise VFR should prevail. An upper level low which is currently sitting just SW of the islands should continue drawing up mid and upper level clouds from the south through the forecast period as well as provide a slight chance of thunderstorms over the waters west of Kauai and Oahu.
AIRMET Zulu is in effect over the state for light icing btn 140 and FL210. Conditions should continue through tomorrow morning and could even be moderate icing at times.
AIRMET Tango is in effect for tempo moderate upper level turbulence between FL250 and FL380. This should continue through at least tomorrow.

Marine

High pressure far northeast of the area will weaken before a front stalls and weakens north of the area midweek, allowing a gradual weakening of the trade winds. A Small Craft Advisory (SCA) is posted for the typical windy waters around Maui County and the Big Island through tonight. A weak ridge will nose in to the north through the latter half of the week before another front approaches. Trade winds will likely maintain at moderate strength through the week.
The current north-northwest (340 degree) swell will gradually decline tonight before a small to moderate, short to medium period north- northwest (330-340 degrees) swell may push surf along north and west facing shores back near seasonal average on Monday, then decline Tuesday. As this swell fades on Wednesday, a moderate short-period north swell will produce a brief boost in north shore surf. Since the storm generating the swell will be compact and fast-moving, there is some uncertainty as to the potential surf height, though it appears that near seasonal average is likely at this time. A new northwest swell will bring surf heights near advisory levels next weekend along exposed north and west facing shores.
Rough surf along east facing shores will decrease through midweek as trade winds decrease. While wind wave energy is not expected to change much midweek, the above mentioned north swell could increase surf along some exposed eastern shores.
South facing shores will experience mainly small background swell through the week.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Kauai Now Weather is brought to you by Blue Hawaiian Helicopters.