West Kaua’i

Tonight: Breezy. Mostly clear with isolated showers. Lows 68 to 73 near the shore to around 61 above 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Tuesday: Breezy. Mostly sunny with isolated showers. Highs around 87 near the shore to around 73 above 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Tuesday Night: Mostly clear with isolated showers. Lows 67 to 73 near the shore to around 60 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

South Kaua’i

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 66 to 76. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Tuesday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 80 to 87. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Tuesday Night: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 66 to 76. East winds around 15 mph. Chance of rain 40 percent.

Kaua’i Mountains

Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then scattered showers after midnight. Lows 62 to 69 in the valleys to around 57 above 4000 feet. East winds 15 to 25 mph. Chance of rain 70 percent.

Tuesday: Breezy. Partly sunny with scattered showers. Highs 74 to 83 in the valleys to around 66 above 4000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tuesday Night: Breezy. Mostly cloudy with scattered showers. Lows 62 to 68 in the valleys to around 57 above 4000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

North Kaua’i

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 66 to 74. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Breezy. Partly sunny with scattered showers. Highs 77 to 85. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday Night: Partly cloudy with scattered showers. Lows 66 to 73. East winds 10 to 15 mph. Chance of rain 40 percent.

East Kaua’i

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 62 to 75. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Breezy. Partly sunny with scattered showers. Highs 75 to 84. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday Night: Mostly cloudy with scattered showers. Lows 64 to 75. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

High pressure far north of the Hawaiian islands will maintain a moderate to locally windy trade wind pattern over the region into the middle of the week. An area of showers moving in on the trades tonight will maintain passing showers over the windward and mountains into Tuesday. Moderate trades and fewer showers are expected during the second half of the week, with an increase in shower trends this weekend.

Short term update

Cloud bands riding into the islands on the brisk trade winds will continue to produce periods of showers favoring the windward mountain areas of all islands through early Tuesday morning.
The afternoon forecast grids look good, no evening updates.

Previous discussion

Issued at 319 PM HST Mon Oct 19 2026 The forecast for tonight has been updated to increase PoPs and associated fields for the windward sides of the islands, particularly over Maui County and the Big Island with an area of showery low clouds riding in on the trade wind flow. Satellite derived precipitable water (PW) shows values 1.3 inches upstream of the islands. The afternoon soundings at Lihue and Hilo had 1.19 and 1.06 inches of PW respectively. The 1.3 is near normal for this time of year, so just expecting a few more showers than we have been seeing in the last couple of days.
High pressure far to the north will linger into Wednesday, with a tight pressure gradient over the islands maintaining the moderate to locally breezy trades. A few sites in the windiest locations (along ridges) have seen winds briefly reach advisory levels, but not expecting any widespread or persistent advisory conditions so have held off on any headlines. There is good model agreement with the ECMWF and GFS models that the high will weaken Wednesday as a strong low, currently far to the northwest in the Western Pacific, moves to the east and sets up far north-northwest of the islands. The high will weaken and move to the east, as the low deepens, and an associated front moves closer to the islands over the weekend.
With the high weakening, the pressure gradient over the islands will weaken, and winds are expected to return to moderate levels. A drier airmass moving over the islands will result in fewer showers during the Wednesday through Friday time period.
As the above mentioned front moves closer to the islands this weekend, moisture will be drawn northward over the islands, increasing shower activity. And then the second half of the weekend and into next week, the tail end of a front may impact the northern islands by increasing shower activity.

Aviation

Issued at 319 PM HST Mon Oct 19 2026 Breezy trades will persist through tomorrow. Passing showers will mainly be concentrated in windward and mountain areas. These showers may produce short-lived MVFR ceilings and visibility.
AIRMET Tango remains in effect for tempo moderate turbulence downwind of terrain below flight level 090.

Marine

Issued at 319 PM HST Mon Oct 19 2026 High pressure centered far north of Hawaii will maintain fresh to strong trade winds for the next few days, and a Small Craft Advisory (SCA) remains in effect for all waters except windward Big Island through Tuesday afternoon. Trades will steadily decrease early Wednesday morning as the high weakens and is displaced eastward by an approaching low far northwest of the islands. The SCA will likely be trimmed back to the typically windy waters around Big Island and Maui at that time. Trade winds will lower to gentle strength, or may become disrupted entirely, as the low passes to the north Thursday and Friday. Trades could then turn more northeasterly this weekend.
Declining north-northwest and west-northwest swells will keep small to tiny surf in place over the next few days before a small northwest swell gives a slight bump to north shores on Thursday and Friday. This will then be followed by a slightly larger north- northwest swell this weekend and a potentially larger long period west- northwest swell early next week from a forecasted storm force low developing northeast of Japan in the next few days.
Small background south swells will keep relatively small surf for south facing shores through much of the week. A moderate south- southwest swell is expected this weekend, and could bring surf heights above seasonal averages.
Rough trade wind swell will produce east shore surf just above seasonal average through Tuesday, then decline later in the week as trade winds decrease.

Fire weather

Issued at 319 PM HST Mon Oct 19 2026 Fire weather will remain below critical levels for the next several days. The subsidence temperature inversion near Maui and the Big Island will remain in the 7000 to 8000 foot range.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Tuesday for most Hawaiian waters and channels.

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Data Courtesy of NOAA.gov