A slow-moving Kona low has brought heavy rainfall to parts of Hawaii over the past five days, with the National Weather Service in Honolulu documenting multiple daily rainfall records at individual stations, including some benchmarks dating back to 1951. Preliminary readings through March 15, 2026, compiled by NWS Honolulu, show several stations on Oahu, Maui, and the Big Island exceeding prior records. With the system still lingering and additional rain possible, Governor Josh Green has issued a second emergency proclamation, and flood risks remain elevated for communities already saturated by days of downpours.
Five Days of Rain Rewrite the Record Books
The National Weather Service office in Honolulu released preliminary totals measured through 10 a.m. HST on March 15, 2026. The data covers station-by-station readings across Oahu, Maui, and the Big Island, and the numbers tell a consistent story: accumulations far exceeded what forecasters initially projected when the Kona low first stalled over the island chain.
What makes this event historically significant is the specific records it erased. At Kahului Airport on Maui, gauges recorded 1.01 inches on March 11, 2026, well above the prior daily maximum of 0.53 inches, according to record reports from NWS Honolulu. That old mark had persisted for decades. The Kahului break is just one entry on a growing list of shattered benchmarks documented in the office’s record event tracking system, which catalogs each new record alongside the date, the amount, and the prior high it replaced.
For residents, the distinction between a heavy rain event and a record-setting one is not academic. When rainfall approaches or exceeds historical records, drainage systems and waterways can be stressed, and localized flooding can develop quickly. Streams and culverts sized for typical historical conditions may be overwhelmed during unusually intense downpours. In communities across the islands, the prolonged rainfall has heightened concerns about flooding where soils and drainage are already saturated.
1951 and 2006: The Benchmarks That Fell
Many of the records broken during this Kona low trace back to March 1951, a month that left a deep imprint on Hawaiian climate data. NWS Honolulu maintains archived rainfall guidance for Honolulu and other stations, and those tools confirm that 1951 set benchmarks still referenced in official climate tables. The federal Climate Data Online portal, available through the National Centers for Environmental Information at NCEI records, provides quality-controlled historical precipitation data from that era for stations including Honolulu International Airport and Lihue Airport, allowing direct comparison with current readings…