Garden Isle sees little rainfall despite passing hurricane in August

Kauaʻi had dry conditions during the month of August despite a passing hurricane that brought several inches of rain to portions of the state.

On Aug. 24, Hurricane Hone passed just south of the Big Island resulting in heavy rainfall along the east- and southeast-facing slopes. Despite several inches of rain falling on Hawai‘i Island, Kaua‘i remained relatively dry.

All of the gauges on the Garden Isle posted below-average monthly totals. The U.S. Geological Survey’s rain gauge on Mount Waiʻaleʻale had the highest monthly total of 13.84 inches, but this amount was just 40% of the August average, according to the National Weather Service’s monthly summary report.

Records for the lowest August rainfall total were broken at Hanapēpē and Wainiha. Mount Waiʻaleʻale, Hanalei, and Kapahi had their lowest August totals since 2005, and Līhuʻe Airport posted its lowest August total since 2007.

Rainfall totals for 2024 through the end of August were near to above average at most of the gauges on Kauaʻi. The Mount Waiʻaleʻale rain gauge had the highest year-to-date total of 231.36 inches (88% of average).

Hurricane Hone dumped rain on the Big Island from Aug. 24-25 with prolonged periods of heavy rainfall along the east- and southeast-facing slopes. The highest 2-day total was 33.58 inches from the manually recorded CoCoRaHS rain gauge in Volcano Village near the summit of Kīlauea.

Before Hone’s passage, August weather around the main Hawaiian Islands included persistent trade winds at mostly moderate to fresh levels. On Aug. 15, a weak surface low-pressure trough moved across the island chain, producing a brief uptick in rainfall. This trough was the remnant of Tropical Cyclone Emilia that dissipated well east of the state. Rainfall totals were mostly less than an inch, and no flood impacts were related to this rain event.

After Hone’s passage, the remnant of Tropical Cyclone Gilma passed just north of the state on Aug. 30. Moisture associated with the remnant produced enhanced rainfall along the east-facing slopes of the Big Island, Maui, Molokaʻi, and Oʻahu. The windward slopes of Haleakalā on Maui had the most rainfall from this event, with 2 to 4 inches estimated over the Keʻanae area.