Rainfall varies widely around island


How rainy was July on the Big Island? The answer varies widely, depending on location.

The South Hilo and Puna districts received what National Weather Service hydrologist Kevin Kodama described as “mostly near average” rainfall for the month. Meanwhile, most leeward rain gauges, especially in the Kona and Ka‘u coffee belts, saw an abundance of rain in July, even taking into consideration summer is the rainy season in those areas.


Still, it remains a drier than normal year for much of Hawaii Island, especially on the windward side.

Hilo International Airport logged 9.56 inches of rain in July, 88% of its average of 10.81 inches for the month. That brings the yearly total at the airport to 47.99 inches, 68% of its usual 70.09 inches.

Mountain View was somewhat wetter, with 12.87 inches in July, 84% of its norm of 15.28 inches.

Pahoa had a slightly wetter than normal month with 11.48 inches, 101% of its July average of 11.38 inches.

Ellison Onizuka Kona International Airport had just 0.88 inches of rain in July. That, however, is 126% of its norm of 0.7 inches for the month. The airport has received just 5.07 inches for the year, a little less than half of its average of 10.72 inches for the first seven months.

Kona’s coffee belt kicked off its summer with a wet July. Waiaha received 12.03 inches of rain last month, more than 2 1/2 times its July average of 4.8 inches. It’s been an extremely wet year in Waiaha, with 44.79 inches of rain, just 0.2 inches below the yearly total for Hilo in 2019, and 157% of its year-to-date norm of 28.44 inches.

Kealakekua and Honaunau also were blessed with a rainy July, the former logging 11.24 inches for the month and the latter receiving 11.3 inches, well above their monthly norms. Kealakekua has received 44.41 inches for the year, 135% of its norm, while Honaunau has tallied 38.53 inches, 20% above average for the year.

“Honaunau had its highest July total in a data record going back to 1993, and Kealakekua had its highest July total since 2004,” Kodama said in his monthly rainfall summary. “In contrast, the Kamuela and Kamuela Upper gauges had their lowest July totals since 2004.”

The two Kamuela gauges referred to by Kodama, both in South Kohala, logged 1.54 and 2.55 inches for July, respectively. That brings Kamuela Upper to 33.13 inches for the year, 84% of its norm of 39.33 inches, while Kamuela had 30.13 inches for the first seven months, 79% of its average of 38.14 inches.

Ka‘u also had rainfall totals well above normal.

Pahala’s July total of 5.33 inches is more than 1 1/2 times its monthly norm of 3.36 inches. And Kapapala Ranch logged 6.43 inches in July, 162% of its norm of 3.97 inches. Pahala reports slightly more than 27 inches for the year, almost 90% of its yearly total, while Kapapala has received 30.5 inches, exactly its average for January through July.

Some areas of Hawaii County continue to experience drought conditions, according to Kodama. In a drought information statement, he said ranchers and the U.S. Department of Agriculture’s Farm Service “continue to indicate extremely poor pasture conditions in the South Point area, with little to no useful forage.”

“Below average rainfall has also started to impact the ginger crop along the Hamakua Coast near Umauma and Hakalau. Vegetation is also reported to be very dry near Hawi,” Kodama said.

Hurricane season continues through the end of November, and it’s been an active year for tropical cyclones, with seven named storms and four hurricanes in the Eastern and Central Pacific, so far.

There are two tropical disturbances in the Eastern Pacific forecasters are keeping their eyes on.

One, about 1,000 miles south-southwest of Mexico’s Baja Peninsula as of Friday afternoon, isn’t expected to organize into a tropical cyclone this weekend, but forecasters give it a 40% chance of developing into one within five days.


A second, hugging the southern coast of Mexico, has a higher chance of developing into a cyclone soon. Forecasters say this disturbance is sending rain bands inland over the Mexican state of Oaxaca and give it a 20% chance of organizing into a cyclone this weekend, and 40% during a five-day period.

Email John Burnett at jburnett@hawaiitribune-herald.com.

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