West Kaua’i

Rest Of Tonight: Mostly clear. Lows around 73 near the shore to around 64 above 3000 feet. East winds up to 15 mph.

Friday: Sunny. Isolated showers in the afternoon. Highs 85 to 90 near the shore to around 76 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Friday Night: Partly cloudy with isolated showers. Lows 71 to 76 near the shore to around 62 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Rest Of Tonight: Partly cloudy. Breezy. Isolated showers after midnight. Lows 70 to 77. Northeast winds 15 to 20 mph. Chance of rain 20 percent.

Friday: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 80 to 89. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Friday Night: Breezy. Mostly cloudy with scattered showers. Lows 69 to 77. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Kaua’i Mountains

Rest Of Tonight: Partly cloudy with isolated showers early in the evening, then mostly cloudy with scattered showers after midnight. Lows 66 to 71 in the valleys to around 62 above 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 75 to 83 in the valleys to around 68 above 4000 feet. Northeast winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Gusts up to 35 mph. Chance of rain 50 percent.

Friday Night: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 63 to 69 in the valleys to around 60 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

North Kaua’i

Rest Of Tonight: Partly cloudy. Scattered showers after midnight. Lows 64 to 75. East winds up to 15 mph. Chance of rain 40 percent.

Friday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 71 to 87. East winds up to 15 mph. Chance of rain 50 percent.

Friday Night: Mostly cloudy with scattered showers. Lows 62 to 75. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Rest Of Tonight: Partly cloudy with isolated showers early in the evening, then mostly cloudy with scattered showers after midnight. Lows 66 to 77. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Friday: Partly sunny with scattered showers. Highs 78 to 86. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Friday Night: Mostly cloudy with scattered showers. Lows 65 to 76. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A high pressure system far northwest of the Hawaiian Islands will slowly drift from west to east over the next few days. This passing system will increase easterly trade winds into the moderate to breezy range lasting into the middle of next week. Brief pulses of enhanced showers are forecast with three passing easterly waves during this time period. Increasing shower trends will favor the windward mountain areas in the overnight to early morning hours starting Friday night and lingering into Tuesday morning. The strongest of these three waves will pass through the islands from late Sunday through late Monday.

Short term update

Minor updates were made to PoPs to account for recent trends. Otherwise previous forecast is on track.

Prev discussion

Issued at 301 PM HST Thu Oct 15 2026
Radar showed scattered windward and mauka showers over each island this afternoon, with additional Kona showers developing. Northeast trade winds were a little stronger than yesterday, averaging 10 to 20 mph with gusts 20 to 30 mph fairly common.
A large surface high continues to strengthen to our north. Aloft, a weak upper level low to our east will become a trough that stretches from southern CA all the way out to us. The trough will be weak, and apart from a slight increase in instability, we won't see much from it.
Several impulses of increased moisture will move west toward and over the state, especially the eastern end, over the coming week. The first will move through Friday afternoon and evening, and reach all islands. We have continued the trend of the previous shift and further increased the chance of rain through this window of time. The second should move over the area late Sunday through late Monday, boosting showers mainly across the eastern end of the state. Again, PoPs have been further increased. Finally, another area may reach us next Thursday, but at this time range confidence is low. Models currently indicate the focus of this one would be on the eastern end.
Trade winds will remain moderate to breezy through the coming week, with the a slight increase possible Tuesday evening. A slight weakening may develop next Thursday, but as mentioned in the previous paragraph, at seven days out, confidence in that level of detail is low.
Finally, both the latest GFS and ECMWF indicate that the upper level trough extending from southern CA over to us may join with energy moving in from the northwest and strengthen toward the middle of next week. It is unclear at this time whether it will develop into a closed low or a stronger trough. Either way, it may draw tropical moisture northward toward the state and present a heavy rain threat. Details should become clearer in a few days.

Aviation

A high pressure system far north of the Hawaiian Islands will drift slowly eastward over the next few days, increasing easterly trade wind speeds. An easterly wave riding into the islands on the easterly trade winds will bring increasing showers spreading from east to west across the islands from Friday afternoon near the Big Island into Saturday across the state. Periods of MVFR conditions and showers will develop over windward mountain areas.
AIRMET Sierra remains in effect for tempo mountain obscuration abv 020 for north and east sections of the Big Island.
AIRMET Tango is in effect for moderate low level turbulence downwind of island terrain.

Marine

Issued at 301 PM HST Thu Oct 15 2026
Surface high pressure far north of the islands will build as it shifts northeast of Hawaii through Saturday. As a result, trade winds will gradually increase to fresh to locally strong levels over the next couple of days. A Small Craft Advisory (SCA) is in effect for the typically windy waters around Big Island and Maui through Saturday and may need to be expanded in area as the high builds to the north. Elevated trade winds will persist into early next week.
The current small bump in the northwest swell will fade tonight before a moderate north-northwest swell arrives Friday. Surf along north and west-facing shores should top out near or slightly above seasonal average during the peak of the swell Friday afternoon and Saturday, then slowly decline late Saturday and Sunday as the dropping swell shifts more northerly and a smaller overlapping northwest swell arrives. Both swells will fade early next week.
A new long-periond south swell will gradually build this evening and may push surf along south-facing shores back above seasonal average into Friday. This swell will slowly decline Saturday through early next week.
Surf along east-facing shores will gradually increase tonight into Friday as trade winds strengthen over the region. Expect some wrap from the moderate north-northwest swell Friday afternoon into Saturday. This swell along with developing rough trade wind swell will produce east shore surf above seasonal average Saturday

Fire weather

Issued at 301 PM HST Thu Oct 15 2026
Surface high pressure north of the islands will produce moderate to breezy trade winds for the next few days. Minimum relative humidity levels will for most areas remain out of critical fire threshold ranges. The stronger trade winds will mainly impact higher elevation areas with even higher minimum humidity levels. Subsidence temperature inversion heights today near Maui and the Big Island should range from 9,000 to 11,000 foot through Friday.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov