Halfway into the dry season for most of Hawaii, 11 Big Island sites experienced their wettest June on record, according to the National Weather Service.
Most prominent among those sites are: Hakalau, with 19.75 inches, seven times its usual June rainfall; Honokaa, with 19.55 inches, four times its June norm; Pahala, with 10.95 inches, five times its June average; and Kapapala Ranch, with 10.68 inches, almost seven times its normal June.
“I was struck by how wet it has been over the past couple of months,” wrote Kevin Kodama, retired National Weather Service Honolulu senior service hydrologist, in his Mauka Showers blog. “… So what produced all this rain? In a broad sense, we’ve had wetter than usual trade winds, including a few trade wind disturbances that boosted rainfall amounts along the windward slopes of the state.”
No windward Big Island spots reported below average rainfall for the month.
Hilo International Airport measured 11.39 inches, 56% above its normal June. Glenwood and Mountain View recorded 20.42 and 19.41 inches, respectively, while Pahoa reported 11.16 inches.
“Looking at Hilo airport’s data from June, the number of days with measurable rain, at least 0.01 inches, was right around normal — 25 days compared to a long-term average of 25.4 days — but the amount of rain per day was well above normal, 0.38 inches per day vs. a long-term average of 0.24 inches per day,” Kodama noted.
“The windward coast and upper slope areas, as well as much of the Puna and Ka‘u districts, fared the best in June, with well above average rainfall in most spots,” said Tina Stall, National Weather Service Honolulu hydrologist. “Much of the Kona and Kohala District coast and slopes, as well as the interior higher elevations, came in below average.”
Ellison Onizuka Kona International Airport in Keahole, which averages less than an inch of rain in June, came in bone dry for the month at 0.04 inches, just 5% of its norm.
Kaloko-Honokohau National Historical Park had less than a quarter-inch of rain, 14% of its June average.
Unlike most of the state, the Kona coffee belt has its wet season in the summer. Two of the four coffee belt gauges — Honaunau with 6.25 inches and Waiaha with 5.39 inches — experienced a normal June. Kealakekua and Kainaliu, with 3.75 inches and 3.6 inches, respectively, were both at 62% of normal June rainfall.
The year-to-date totals for the first half of 2026 were almost all at or above normal levels.
Unsurprisingly, the most robust rainfall totals for the year were recorded on the windward side of the island.
Glenwood, in the upper Puna rainforest, had the highest rainfall total among populated areas with 125.52 inches, almost 10 inches above average.
Mountain View reported 108.22 inches, 29% above its norm for the first six months. And Waiakea Experimental Station, in the foothills above Hilo, registered 108.22 inches — 30% more than its average.
In Ka‘u, the precipitation was equally striking. Pahala received 76.44 inches and Kapapala Ranch recorded 70.9 inches — in both cases, more than twice the normal rainfall for January through June.
Even on the drier leeward side, all but two gauges recorded average or above average rainfall for the year-to-date. Puuanahulu, in the North Kona hills, received 12.04 inches of rain in the first six months, 85% of its norm, and Puhe, just south of Kawaihae on the Kohala Coast, had just 3.7 inches, or 64% of its normal rainfall for the first half of the year.
Kona airport received 9.52 inches of rain for the year, exactly 4 inches more than its half-year average, and the four Kona coffee-belt gauges all have recorded significantly higher-than-average rainfall totals, with Honaunau leading the way at 43.07 inches, 69% above its norm.
No drought remains on the Big Island, although the U.S. Drought Monitor listed 22.69% of the island as abnormally dry — with the parched areas occurring on Daniel K. Inouye Highway and along a portion of the Kohala coastline.
The bountiful rainfall is likely to end at some point in the intermediate future. The Central Pacific Basin is currently experiencing El Nino conditions, a natural climate pattern in which warmer than normal ocean surface temperatures significantly alter the weather.
“The strengthening El Nino will probably be the primary driver of rainfall conditions through the rest of the dry season and into early next year,” Kodama said, adding a computer model posted July 8 “shows probabilities favoring above normal rainfall through the rest of the dry season.”
“The last time we had a very strong El Nino was in 2015,” he noted. “It helped produce the wettest dry season in 30 years and conditions remained fairly wet into mid-December before the El Nino dry pattern finally established itself. If the models are right, this year’s event could bring an earlier start to El Nino-related statewide drought conditions.
“Once established, these conditions will likely persist into the spring of 2027.”
Email John Burnett at john.burnett@hawaiitribune-herald.com.
