Most Big Island Rain Gauges See Near to Below Average Totals in July

Big Island rain gauges reported near to below average rainfall totals for July, according to a rainfall summary for the month from the National Weather Service in Honolulu.

Monthly totals from windward sites on the island were mostly 50%-80% of average, while totals from the Kaʻū, Kona and leeward Kohala areas were mostly below 50% of average, according to Kevin Kodama, senior service hydrologist with the NWS, in his monthly rainfall report.

The U.S. Geological Survey rain gauge at Kawainui Stream had the highest monthly total of 28.50 inches, or 212% of average. The Pi’ihonua gauge had the highest daily total of 3.47 inches on July 13.

Kealakekua and Waikōloa Village had their lowest July totals since 2011.

Big Island rainfall totals for 2022 through the end of July were also near to below average at most gauges. The USGS gage at Kawainui Stream had the highest year-to-date total of 119.80 inches, or 131% of average.

“Trade winds persisted through the entire month of July,” Kodama said in the summary about statewide weather last month. “Intensities were fresh to strong through the Fourth of July, then eased to mostly moderate to fresh levels for the remainder of the month.”

The largest rain event for the state last month was on July 12-13 as remnant moisture of former Tropical Cyclone Bonnie moved across the island chain. Several rainfall totals of 1-4 inches were observed by rain gauges along the windward slopes of the state, with an event maximum of more than 6 inches over the West Maui Mountains.

“A few days later, Tropical Storm Darby provided a brief boost in rainfall over the Big Island as it passed quickly to the south of South Point on July 16 just prior to dissipating,” Kodama said in the summary.

Rain gages along the east-facing slopes of the Big Island recorded about 1-3 inches during Darby’s passage, and there were no significant flooding problems caused by Bonnie or Darby.

But while windward areas of the state received needed rainfall last month, leeward areas remained very dry, with most locations posting rainfall totals at less than 50% of the July average.

“Severe to extreme drought continued in the four main counties across the state,” Kodama wrote. “The worst conditions were in the leeward sections of Maui County and the Big Island.”

For more details, refer to the Drought Information Statement online.

To read the full rainfall summary for July, click here.