West Kaua’i

Today: Cloudy with scattered showers. Highs around 81 near the shore to around 70 above 3000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Cloudy. Numerous showers in the evening, then showers after midnight. Lows around 69 near the shore to around 61 above 3000 feet. East winds up to 10 mph. Chance of rain 80 percent.

Tuesday: Cloudy. Showers early in the morning, then scattered showers in the late morning and afternoon. Highs around 82 near the shore to around 70 above 3000 feet. Southeast winds up to 10 mph in the morning becoming light. Chance of rain 80 percent.

South Kaua’i

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Kaua’i Mountains

Today: Cloudy. Scattered showers until late afternoon, then numerous showers late in the afternoon. Highs 73 to 79 in the valleys to around 63 above 4000 feet. South winds up to 10 mph. Chance of rain 60 percent.

Tonight: Cloudy. Numerous showers until early morning, then showers early in the morning. Lows 64 to 69 in the valleys to around 59 above 4000 feet. South winds up to 10 mph. Chance of rain 90 percent.

Tuesday: Cloudy. Showers early in the morning, then numerous showers in the late morning and afternoon. Highs 73 to 79 in the valleys to around 64 above 4000 feet. Light winds. Chance of rain 90 percent.

North Kaua’i

Today: Cloudy with scattered showers. Highs 73 to 81. South winds up to 10 mph. Chance of rain 50 percent.

Tonight: Cloudy. Scattered showers until early morning, then numerous showers early in the morning. Lows 64 to 71. South winds up to 10 mph. Chance of rain 70 percent.

Tuesday: Cloudy with scattered showers. Highs 73 to 82. Light winds. Chance of rain 50 percent.

East Kaua’i

Today: Cloudy with scattered showers. Highs 70 to 80. South winds up to 10 mph shifting to the southwest in the afternoon. Chance of rain 50 percent.

Tonight: Cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 65 to 73. Southwest winds 10 to 15 mph. Chance of rain 70 percent.

Tuesday: Cloudy with scattered showers. Highs 72 to 82. South winds up to 10 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Light to moderate rain will continue through tonight over the western portion of the state. A few showers may be locally heavy. Quieter weather then settles in for the remainder of the week and light trades return by week's end.

Short term update

Issued at 802 PM HST Sun Apr 12 2026
Latest radar imagery depicts light rainfall continuing over the western portion of the state. The most recent One-Hour Rainfall Summary (730 PM HST) shows most locations that are experiencing rain are receiving under a tenth of an inch in the last hour, with some areas a bit higher. The Flood Watch remains in effect through 6 AM HST Monday and will be reevaluated with the morning forecast package. Otherwise, the current forecast remains on track and no major amendments have been required this evening.

Prev discussion

Nil instability, weak forcing, and rather high mid-level static stability have allowed Oahu to dodge a potentially impactful flooding event. Little change is expected during the next several hours, so rain rates are expected to remain in check. Cancelling the Flood Watch for Big Island. Will draw back the ending time for Kauai through Maui to 6am tomorrow morning. Elected to retain portions of the Flood Watch to account for the onset of the favorable diurnal cooling period and ongoing convection in Maui County within the surface trough axis. As forcing weakens, so too will rain rates. Light showers and mid-level clouds are likely to linger over the western end of the state for the balance of the week before another shortwave pivots through and brings a slight uptick in rainfall on Friday or Friday night. This wave is modeled to be progressive and and likely not impactful.
Despite the grungy pattern that may hang over Kauai and Oahu through the week, for the first time in awhile, there is no potential event on the horizon. The large scale pattern is gradually migrating away from aggregate low pressure anchoring north of the islands, though high pressure struggles to build as the mid-latitudes transition toward a more progressive pattern. Light winds favoring onshore sea breezes each afternoon may trigger rather productive convection in terms of showers as the moisture-rich airmass lingers. Likewise, dewpoints will hover around 70 degrees until the dregs of this airmass are ushered westward by returning trades. Trades do return by late this week, but remain quite light and may not make much of a dent in local humidity.

Aviation

Issued at 802 PM HST Sun Apr 12 2026
Low cigs and SHRA will continue over the islands through the overnight into tomorrow. MVFR and some isol IFR conds possible especially across the western side of the state. Winds should remain light.
AIRMET Sierra is in effect for mtn obsc for Kauai to Maui. This may be expanded to include the Big Island.
AIRMET Tango is in effect for mod turb btn 120-FL280. Conds should slowly improve into tomorrow.

Marine

A weak surface trough will linger in the vicinity of the central and northwestern islands into early next week, keeping moderate to fresh southeasterly winds to its east, and light to moderate southerly winds to its west. This weak surface boundary along with an upper level disturbance moving over the region is currently bringing another round of showers and the potential for isolated thunderstorms this afternoon into Monday. As the surface trough lifts northwest and high pressure to the northeast begins to take over at the surface, gentle to moderate easterly trades will gradually develop across the Hawaiian coastal waters by the end of the week.
A moderate, medium-period north-northwest swell (340 degrees) generated by the formerly-gale force low north-northwest of the main Hawaiian islands is filling in along north and west facing shores this afternoon. This swell will maintain small to moderate surf through Monday, followed by a decline in northwest swell energy for the rest of the week.
A medium-period south swell will continue to decline through Monday. By Tuesday, however, a new south swell will arrive, once again providing a boost to surf along south facing shores through mid week before gradually subsiding into the weekend.
Surf along east facing shores will remain below seasonal average with lighter than average trade winds near and upstream of the islands forecast through next week.

HFO Watches/Warnings/Advisories

Flood Watch until 6 AM HST Monday for Niihau, Kauai, Oahu, Molokai, Lanai, Maui, and Kahoolawe.

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Data Courtesy of NOAA.gov