Hawaii is 42.70 inches wetter than normal this year, its wettest January through September on record

Hawaii has soaked up an average of 86.66 inches of rain statewide since the start of January, according to NOAA’s National Centers for Environmental Information. The total is the wettest January through September NCEI has on record for the state, and it came after a September in which Hurricane Lowell helped push the islands to one of their wettest months in decades.

The finding sits inside NCEI’s national summary for September 2026, published on October 8. Most of the attention in that summary goes to the mainland, where drought and flooding rains sit side by side, but the Hawaii numbers are the most lopsided in the document.

The nine-month total and what it means

NCEI reports that Hawaii’s year-to-date rainfall through September averaged 86.66 inches, which is 42.70 inches above the 1991 to 2020 normal, and calls it the wettest January through September on record. The figure is a statewide average, so it blends windward slopes that routinely receive enormous totals with leeward coasts that are typically dry. A surplus of 42.70 inches against a normal near 44 inches means the state has received roughly double what a typical year to date would deliver.

The phrase “on record” needs a boundary around it. NCEI describes Hawaii’s climate record as 36 years long for this analysis, so the claim covers that modern span rather than the full history of island weather, which stretches back much further in other archives. Rankings in NOAA’s monitoring products are defined by a specific ranking convention, and a first-place finish in a short record is a strong statement about recent decades while leaving older decades unmeasured by this dataset.

September, Hurricane Lowell and the final push

September itself was a standout. NCEI’s summary says the month totaled 10.83 inches of rain across Hawaii, 6.42 inches above the 1991 to 2020 average, making it the wettest September since 2015 and the second-wettest September in the 36-year record. The agency notes that Hurricane Lowell contributed to that total. The page offers no breakdown of how much of the month’s rain fell during the storm’s passage, so the share attributable to Lowell is not established here.

Because September alone added 6.42 inches of the surplus, it explains only a modest part of the year’s 42.70-inch excess. Subtracting it leaves about 36.28 inches of surplus built up between January and August, which makes the larger story one of accumulation: the first eight months were already running far above normal before Lowell arrived, and September then widened a lead that was already a record. The summary does not break out monthly departures for the earlier months, and no individual month before September is singled out in the portion of the report that has been published.

Warmth accompanied the wetness, and the temperature numbers are record-grade in their own right. The same summary puts Hawaii’s September average temperature at 71.1 degrees Fahrenheit, 2.1 degrees above average and the second-warmest September in the record, with minimum temperatures averaging 65.0 degrees, 3.6 degrees above average and the warmest September minimums on record.

A very different September on the mainland

The Hawaii result is easier to read against the rest of the country, where NCEI documents a split. Drought covered 89 percent of the South region according to the U.S. Drought Monitor map for September 29, which NCEI describes as the largest extent for the region since October 2000. Behind that headline sit weekly tallies that the Drought Monitor publishes as data tables for anyone who wants to track the region week by week.

In the Southwest the story ran the other way. Arizona averaged 2.97 inches of rain in September, 251.7 percent of average, its wettest September since 1983. New Mexico received more than 5 inches, 303.6 percent of average, its wettest September since 1941. Both states rank second-wettest in their records for the month, so the same September that left much of the South parched delivered its heaviest September rain in decades to the desert Southwest, according to the NCEI figures. The contrast is the reason the summary reads as a patchwork rather than a single national verdict.

Superlatives like these are collected in NCEI’s record-setters listing for September 2026 and in a companion table of county-level superlatives, which are the places to check whether a particular island or county stood out within the statewide average. Readers who want to rebuild the Hawaii rankings can also use NCEI’s Climate at a Glance mapping tool, which is a reference page for the national data rather than a source of the figures above.

The full September 2026 U.S. climate report is scheduled for release on October 14, 2026, and its detailed state sections may refine how the Hawaii numbers are presented. Until then, the published summary supports three plain statements: Hawaii’s January through September rainfall is the highest in NCEI’s record, September ranked second in that record, and a tropical system was among the contributors to the final month’s total.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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