West Kaua’i

Tonight: Occasional showers until early morning, then showers likely late in the night. Lows around 66 near the shore to around 58 above 3000 feet. Southeast winds 10 to 15 mph. Chance of rain near 100 percent.

Monday: Cloudy with scattered showers. Highs around 81 near the shore to around 69 above 3000 feet. Southeast winds 10 to 15 mph. Chance of rain 50 percent.

Monday Night: Cloudy with scattered showers. Lows around 69 near the shore to around 61 above 3000 feet. South winds around 10 mph. Chance of rain 50 percent.

South Kaua’i

Tonight: Occasional showers. Lows around 67. East winds around 10 mph in the evening becoming light. Chance of rain near 100 percent.

Monday: Cloudy. Occasional showers early in the morning, then showers likely late in the morning. Scattered showers in the afternoon. Highs 75 to 81. Light winds. Chance of rain 90 percent.

Monday Night: Cloudy with scattered showers. Lows around 70. Light winds. Chance of rain 40 percent.

Kaua’i Mountains

Tonight: Occasional showers. Lows 60 to 66 in the valleys to around 57 above 4000 feet. Southeast winds around 10 mph. Chance of rain near 100 percent.

Monday: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 73 to 79 in the valleys to around 63 above 4000 feet. South winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 70 percent.

Monday Night: Cloudy with scattered showers. Lows 63 to 69 in the valleys to around 59 above 4000 feet. South winds up to 15 mph. Chance of rain 50 percent.

North Kaua’i

Tonight: Cloudy. Occasional showers early in the evening, then showers likely in the late evening and overnight. Lows 61 to 68. Southeast winds around 10 mph. Chance of rain 90 percent.

Monday: Cloudy. Showers likely early in the morning, then scattered showers in the late morning and afternoon. Highs 73 to 81. South winds up to 10 mph. Chance of rain 70 percent.

Monday Night: Cloudy. Scattered showers early in the evening, then isolated showers in the late evening and overnight. Lows 63 to 72. South winds up to 10 mph. Chance of rain 40 percent.

East Kaua’i

Tonight: Occasional showers. Lows 62 to 70. Light winds becoming southeast around 10 mph after midnight. Chance of rain near 100 percent.

Monday: Cloudy. Occasional showers early in the morning, then scattered showers in the late morning and afternoon. Highs 70 to 80. South winds around 10 mph. Chance of rain 90 percent.

Monday Night: Cloudy with scattered showers. Lows 65 to 73. Southwest winds around 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