West Kaua’i

Tonight: Partly cloudy with isolated showers. Lows around 74 near the shore to around 63 above 3000 feet. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs 85 to 92 near the shore to around 78 above 3000 feet. Light winds. Chance of rain 20 percent.

Wednesday Night: Mostly clear. Isolated showers in the evening. Lows around 74 near the shore to around 64 above 3000 feet. Light winds. Chance of rain 20 percent.

South Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 71 to 77. Northeast winds 10 to 15 mph. Chance of rain 30 percent.

Wednesday: Partly sunny with scattered showers. Highs 79 to 90. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Wednesday Night: Partly cloudy with isolated showers. Lows 71 to 77. Northeast winds around 10 mph. Chance of rain 20 percent.

Kaua’i Mountains

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows around 69 in the valleys to around 61 above 4000 feet. Light winds. Chance of rain 40 percent.

Wednesday: Partly sunny with scattered showers. Highs 76 to 83 in the valleys to around 74 above 4000 feet. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 50 percent.

Wednesday Night: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows around 69 in the valleys to around 62 above 4000 feet. East winds around 10 mph. Chance of rain 30 percent.

North Kaua’i

Tonight: Partly cloudy with scattered showers. Lows 65 to 75. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Wednesday: Mostly sunny with scattered showers. Highs 72 to 87. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 40 percent.

Wednesday Night: Partly cloudy with isolated showers. Lows 65 to 75. East winds around 10 mph. Chance of rain 20 percent.

East Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 67 to 77. Light winds. Chance of rain 40 percent.

Wednesday: Partly sunny with scattered showers. Highs 79 to 87. Light winds becoming east around 10 mph in the afternoon. Chance of rain 40 percent.

Wednesday Night: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 67 to 77. Northeast winds around 10 mph. Chance of rain 30 percent.

Detailed Forecast

Synopsis

A more seasonal trade wind pattern has returned to the state with the exit of Hurricane Lala. Expect typical trade wind showers focused along windward and mauka areas through tonight. Trade winds weaken Wednesday into the latter half of the week as a trough passes northeast of the islands. The trough also brings an increase in moisture that will produce an uptick in shower activity through Friday. This weekend, trade winds restrengthen.

Short term update

Forecast looks on track for tonight and Wednesday, so no updates are anticipated this evening.

Prev discussion

Issued at 344 PM HST Tue Aug 18 2026
The return of the trade winds will bring areas of showers over windward and mauka locations through tonight. Trades weaken Wednesday through Friday as a trough passes northeast of the islands. Lighter trades will increase precipitation chances for leeward areas with the development of a sea/land breeze pattern.
The winds are expected to strengthen and shift easterly late Friday into Saturday, which will pull additional moisture into the area. This will increase precipitation chances for early in the weekend. Highest chances will be on the windward and mauka parts of the islands.
For Sunday and Monday, tropical moisture is expected to be in the vicinity of the state due to the potential development of a tropical system. Most guidance keeps the track of the potential tropical system south of the islands. While there remains uncertainty in the forecast since the system has yet to develop, precipitation chances have been increased for early next week. Please continue to monitor the forecast as it is subject to change as we get closer to the weekend and details surrounding the forecast become clearer.

Aviation

Moderate trades expected through tomorrow. Some windward and mauka SHRA possible with isol MVFR conds. VFR conditions should prevail.
No AIRMETs are currently in effect.

Marine

High pressure far northeast of the waters will remain nearly stationary and slowly weaken for the next couple of days. Trade winds will continue a weakening trend, becoming light and variable for most waters by Thursday as daytime sea breezes and overnight land breezes become established. By late Friday, moderate to locally fresh trades will begin to build back into the region as the high drifts southward closer to the island chain. Heading into the weekend, the potential development of a tropical system southeast of the islands is possible but uncertainty remains as the system has yet to develop.
Surf along south facing shores will continue declining through midweek as south swell fades. Another long period south swell generated from gales just south and east of New Zealand will begin arriving late this week. Surf along east facing shores will also continue to fade as background flow becomes weaker. North facing shores will remain tiny throughout the week.

Fire weather

Issued at 340 PM HST Tue Aug 18 2026
Moderate trade winds will prevail through tonight. Trade winds will weaken Wednesday through Friday, increasing chances of showers for the leeward side of the islands. Trade winds increase over the weekend into early next week with increased chances of precipitation. The inversion is 6000 to 7000 ft.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov