West Kaua’i

Tonight: Mostly cloudy. Lows around 69 near the shore to around 58 above 3000 feet. West winds 10 to 15 mph.

Monday: Cloudy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to around 68 above 3000 feet. West winds up to 10 mph. Chance of rain 30 percent.

Monday Night: Cloudy with scattered showers. Lows around 67 near the shore to around 58 above 3000 feet. Northwest winds up to 10 mph. Chance of rain 30 percent.

South Kaua’i

Tonight: Mostly cloudy. Lows around 68. West winds 10 to 15 mph.

Monday: Cloudy with isolated showers. Highs 76 to 82. West winds up to 10 mph. Chance of rain 20 percent.

Monday Night: Cloudy with scattered showers. Lows around 67. West winds up to 10 mph in the evening becoming light. Chance of rain 30 percent.

Kaua’i Mountains

Tonight: Mostly cloudy. Breezy. Lows 61 to 67 in the valleys to around 56 above 4000 feet. West winds 10 to 25 mph decreasing to up to 20 mph after midnight. Gusts up to 45 mph.

Monday: Cloudy and breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs 71 to 77 in the valleys to around 61 above 4000 feet. West winds up to 20 mph. Chance of rain 40 percent.

Monday Night: Cloudy with scattered showers. Lows 60 to 66 in the valleys to around 56 above 4000 feet. West winds up to 15 mph. Chance of rain 40 percent.

North Kaua’i

Tonight: Mostly cloudy. Lows 62 to 70. West winds up to 15 mph.

Monday: Cloudy. Isolated showers late in the morning. Scattered showers in the afternoon. Highs 71 to 80. Southwest winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 40 percent.

Monday Night: Cloudy with scattered showers. Lows 60 to 69. Northwest winds up to 10 mph. Chance of rain 40 percent.

East Kaua’i

Tonight: Mostly cloudy. Lows 62 to 72. West winds up to 15 mph.

Monday: Cloudy. Isolated showers in the late morning and afternoon. Highs 69 to 81. Light winds becoming southwest up to 10 mph in the afternoon. Chance of rain 20 percent.

Monday Night: Cloudy with scattered showers. Lows 62 to 70. Light winds. Chance of rain 30 percent.

Detailed Forecast

Synopsis

Periods of moderate to heavy rain continue over Leeward Big Island and Maui while conditions improve elsewhere. There is a threat for heavy rain during the latter half of this week as low pressure develops west of the islands.

Short term update

Issued at 820 PM HST Sun Mar 15 2026
The kona low has meandered well north of the islands; however, showers continue to sock in Maui County and the Big Island, where Flash Flood Watches remain in place. It's anticipated that showers will ease throughout the overnight period, allowing the aforementioned Watch to be canceled by the morning forecast package. Meanwhile, latest observations continue to depict the summits of Big Island gusting well above High Wind Warning threshold. Model guidance suggests these winds will fall below threshold around the time of the next package, warranting the downgrade to a Wind Advisory; however, this will be reassessed later tonight. Largely, the forecast remains on track, so apart from just updating the winds and temperatures with the latest trends, no amendments were necessary at this time.

Prev discussion

Moisture embedded within deep layer SW flow extends well upstream of the Big Island and will continue to deliver waves of rainfall through at least Monday night and potentially Tuesday. However, the lack of large scale forcing during this time will likely result in a trend toward lower intensity rainfall compared to what was observed yesterday or even today. At the same time, the weakening background wind field may allow the overnight mountain breeze to more effectively focus stronger convection offshore at night. Rather nondescript surface pressure and wind fields takes shape during Tuesday which should finally bring an end to the steady stream of rainfall. At this time, the Flood Watch will remain in effect for the Big Island and Maui, though confidence in the moisture band lifting sufficiently far north to impact Maui again is low at this time. The Wind Advisory will end with issuance of the afternoon forecast package, and the High Wind Warning for Haleakala and the Big Island summits will be extended through tonight.
Attention then turns to mid to late week when the remnant frontal band reactivates in response to renewed mid/upper forcing followed by potential development of low pressure west of the islands during the second half of the week. The first upper wave arrives late Wednesday. Mid- level flow will still be southwesterly at this time, though it is uncertain whether boundary layer flow will will be in a state of weak trades of out of the south. In any case, an uptick in showers is anticipated over the islands by Wednesday night. Surface pressure falls will already be taking place upstream of the islands during this time as a trailing upper wave approaches the islands from the northwest. Model consensus previously broke down at this point with the GFS indicating a flatter and more progressive surface low while the EC indicated a deeper and slower moving low. The most recent run of the GFS has made a strong move toward the EC increasing confidence that organized low pressure will develop over or near the islands by late this week. Moderate to heavy rain then potentially develops over the islands as early as Friday and would continue into the weekend.

Aviation

Issued at 820 PM HST Sun Mar 15 2026
The system that has plagued the area continues to move northeast. Low cigs and SHRA continue across the area and will slowly decrease from west to east tonight into tomorrow. Some MVFR conds are possible. The lone exception is Lanai which is LIFR with fog thats expected to last into the morning. Winds have weakened over the state and will continue that trend into tomorrow. There still could still be some gusty winds especially over Maui and the Big Island.
AIRMET Sierra is in effect for mtn obsc from Molokai to the Big Island. Oahu may be added especially over windward locations overnight. Conds in general will imp west to east and this AIRMET will be adjusted as necessary.
AIRMET Tango remains in effect for mod mid-upper level turb between 130 and FL330. It is is also in effect for turb downwind N thru E of terrain statewide. As winds diminish and this system moves further away from the islands this will be adjusted in the overnight hours.
Light icing is possible between 130 and FL260 as mid-high clouds continue moving through the islands.

Marine

The kona storm that has impacted the region over the past few days will weaken as it moves northeast and away from the area, with conditions improving over the coastal waters. Latest hi-res guidance shows that locally strong winds may linger over portions of the central and eastern waters tonight. Additionally, buoy observations show that seas remain elevated, with Barber's Point and Hanalei still reporting 10ft and 12ft significant wave heights this afternoon, respectively. Therefore, the Small Craft Advisory (SCA) that was previously in effect has been extended in time through tonight to capture the seas for the western waters and locally breezy winds in the central and eastern waters (with the exception of the Southeast Big Island zone where the SCA has been cancelled). By early Monday, both winds and seas are expected to fall below advisory criteria. Winds will then remain light and variable through mid-week. Ridging is forecast to strengthen north of the islands late in the week, which should bring a return of moderate to fresh trade winds.
Large, rough surf along south-facing shores that has been observed over the past few days will trend lower tonight and Monday as wind speeds subside. A new long-period south swell will arrive late Monday night and Tuesday, giving an extended boost to south shore surf through late this week.
A moderate sized, short-period west-northwest swell will continue to affect north and west facing shores through Monday, but surf will remain below advisory levels. The one exception is for west facing shores of the Big Island, where a High Surf Advisory remains in effect through 6 AM HST. This short-period swell will lower Monday night and Tuesday, while a new medium-period north- northwest swell fills in. This north-northwest swell could bring surf up to advisory levels Tuesday night and Wednesday, with the swell then shifting more northerly and lowering below advisory levels Thursday into next weekend.
Surf along east facing shores will remain well below normal levels through the middle of the week, before trending upward Thursday into next weekend as trade winds return over and upstream of the islands.

HFO Watches/Warnings/Advisories

Flood Watch until 6 AM HST Monday for Big Island East, Big Island Interior, Big Island North, Big Island South, Big Island Southeast, Haleakala Summit, Kahoolawe, Kipahulu, Kohala, Kona, Lanai Leeward, Lanai Mauka, Lanai South, Lanai Windward, Maui Central Valley North, Maui Central Valley South, Maui Leeward West, Maui Windward West, Molokai Leeward South, Molokai North, Molokai Southeast, Molokai West, Molokai Windward, South Haleakala, South Maui/Upcountry, Windward Haleakala.
High Wind Warning until 6 AM HST Monday for Big Island Summits, Haleakala Summit.
High Surf Advisory until 6 AM HST Monday for Kohala, Kona.
Small Craft Advisory until 6 AM HST Monday for Alenuihaha Channel, Big Island Leeward Waters, Big Island Windward Waters, Kaiwi Channel, Kauai Channel, Kauai Leeward Waters, Kauai Northwest Waters, Kauai Windward Waters, Maalaea Bay, Maui County Leeward Waters, Maui County Windward Waters, Oahu Leeward Waters, Oahu Windward Waters, Pailolo Channel.

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Data Courtesy of NOAA.gov