June brought rain to Kona slopes on Hawai‘i Island

June rainfall brought record levels of moisture to the Kona District.

According to the monthly summary report from the National Weather Service in Honolulu, most sites in the Kona District exceeded their monthly averages, several by two to three times their average with gauges in Hōnaunau, Kealakekua and Waikōloa recording their wettest Junes since 1993, 1991 and 2010.

The highest monthly total came from the U.S. Geological Survey gauge at Kawainui Stream with 14.94 inches, or 151% of the average. This site also recorded the highest daily total for the month with 2.64 inches on June 23.

Most windward and interior sites were below average for June, the worst of which were in the Hāmākua District and lower elevations of the Kohala District.

The Kapāpala RAWS station in the Ka‘ū District recorded its second driest June on record since 2012.

June began with high pressure far to the northeast and a deep surface trough to the west of Kauaʻi drew in higher moisture with east-southeast winds. Early morning showers returned June 4–5 along the Kona slopes, totaling 0.5–1 inches.

A decaying front and upper disturbance enhanced rainfall across windward areas on June 6, enhancing windward and mauka showers, with rainfall up to 1.5 inches in some areas, and around 2 inches at Mt. Waiʻaleʻale.

Weaker trades and sea breezes on June 7 and 8 led to afternoon showers along Kona slopes, totalling 0.10 to 1.25 inches, and up to 2 inches near Kealakekua, according to the monthly summary.

Trades strengthened to locally breezy June 11 through June 17 as high pressure built north of the state. Most areas remained dry during this stretch, though a few shallow moisture bands brought scattered windward and mauka showers, the summary indicated.

Gauges recorded up to 0.25 inches on the night of June 12 to June 13, with the highest totals on Hawaiʻi Island and Maui, with widespread showers (0.25 to 0.75 inches, locally near 1 inch) across the islands on the night of the 16th into the 17th.

Beginning on June 18, the trade winds weakened slightly as the high shifted east. Moderate showers fell on the Kona slopes (0.25–1 inches) through June 20. Trades returned to breezy-to-locally-strong by June 21 with minimal rainfall statewide.

The USGS’ rain gauge at Honoliʻi Stream remains the highest year-to-date total with 48.63 inches or 44% of the average. The Kawainui Stream gage was a close second with 48.47 inches or 62% of the average.