July 2026 Monthly Rainfall Summary for Hawaii

Monthly Precipitation Summary 

State of Hawaii 

Month: July 2026

Prepared: August 7, 2026

Note: This summary uses the arithmetic mean, or average, for “normal” rainfall values. 

Averages used in this summary have switched to the 1991-2020 values where available.

State: [Text data table for rain gages]

Headline: Typical summer rainfall distribution with windward and mauka areas generally above average and leeward areas below average for the month of July.

July began with moderate to locally breezy trade winds and typical scattered windward and mauka showers. Stable conditions kept most leeward areas dry, although increased low-level moisture moving through between the 7th and 10th provided a modest increase in windward rainfall.

Breezy trades continued through the 13th under a strong surface high anchored well north of the state. Trade winds briefly weakened on the 14th and 15th as a mid-level trough passed westward over the islands, allowing afternoon sea breezes and upslope showers to develop over leeward areas, particularly for Oʻahu and Maui County. Windward showers also increased slightly, though rainfall totals generally remained at a quarter-inch or less.

Moderate to breezy trades returned through the 22nd, with mostly dry and stable conditions and scattered windward showers. Enhanced low-level moisture produced a period of heavier windward rainfall on the 17th, with some gauges on Maui County receiving around a half inch and several on the Big Island recording 1 to 2 inches or more. Another surge of moisture moved through from the 20th through the 22nd, producing 0.5 to 1.5 inches of rain across many windward areas. Kauaʻi received the most significant rainfall, with 1 to 3 inches across the central higher elevations and extending northward to the coast.

Breezy to locally windy trades continued through the 24th before easing to moderate to breezy speeds. By the 27th, the remnants of Tropical Storm Fausto had moved north of the islands, resulting in light and variable winds. Increased moisture associated with Fausto continued to bring muggy weather statewide and enhanced showers over windward higher terrain on the 27th and 28th, with rainfall amounts generally 1 to 2 inches. Lighter winds also allowed afternoon sea-breeze showers to develop over leeward Oʻahu and Molokaʻi, producing up to around a half inch in some areas.

Moderate to breezy trades and a drier, more stable airmass returned on the 30th and 31st as Fausto's remnants moved away to the northwest and strong surface high pressure rebuilt north of the state.

Island of Kauaʻi : [July 2026 map] [year-to-date map]

The typical summer trade wind shower pattern was on full display this month, with all windward and northern portions of the island, and interior higher elevations coming in above average for July rainfall. The south and western portions, from Kalaheo westward to Mana, came in below average. (30% or less). For the fourth month in a row, the USGS gage on Mt. Waiʻaleʻale had the highest monthly total for the island and the state with 50.28 inches (129% of average), and the highest daily total for the island and the state with 5.91 inches on the 22nd. This gage also had the wettest July in its period of record (since 2003). The USGS Kilohana rain gage came in a very close second for daily total with 5.90 inches on the 28th and also recorded its wettest July since 2010.

The year to date (YTD) totals and percentages of average were still near to above average again this month, but slightly less so than at the end of June, as the impact of the significant late-winter rainfall continues to fade. The highest YTD total still belongs to Mt. Waiʻaleʻale with 298.18” (131% avg).

Island of Oʻahu: [July 2026 map] [year-to-date map]

Typical summer conditions focused rainfall along the Koʻolau Mountains again this month, with most sites in that region coming in near to above average for July. Leeward areas (Waiʻanae through Honolulu) were quite dry this month, with rainfall only 30% or less of their July averages and several in the single digits. Remaining areas of the island, including the rest of the coastal locations and much of the interior valley ended up somewhere between these two extremes, but still below average (around 40 to 80%). The Mānoa Lyon Arboretum Ua Net site had the highest total on the island again this month with 15.54 inches, (101% of average) and the highest daily total of 2.74 inches on the 28th. The Honolulu Airport tied the record for its driest July (period of record since 1940), which was also set in 2017 and 2024.

Despite a poor showing for much of the island in July, the year to date (YTD) totals continue to run well above average for all reporting stations, due to an impressive March performance. The highest YTD total came from the USGS Moanalua RG with 145.43 inches (192% of average). 

Maui County: [Maui July 2026 map] [year-to-date map] [Molokaʻi/Lanaʻi July 2026 map] [year-to-date map]

The typical summer windward rainfall focus continues for Maui County as well, with all of those sites above average for July. Leeward sites were rainfall-starved this month, coming in well below average, including two sites with zero totals. Leeward Lanaʻi fared better than Molokaʻi and Maui, however, with totals ranging from 60 to 80% of average. The USGS Puʻu Kukui gage had the highest monthly total in the county with 42.91 inches (130% of average), as well as the highest daily total of 5.06 inches on the 1st. This site also recorded its wettest July since 2005 (missing data in 2015). Other sites recording their wettest July include the RAWS sites at Makapulapai since 2003 (missing data in 2010 and 2019) and Puʻu Aliʻi since 2015.

The year to date (YTD) totals for all reporting sites in the county were still near to above average (around 100 to 300%). The highest YTD total is still at Puʻu Kukui with 250.09 inches (111% of average). 

Island of Hawaiʻi: [July 2026 map] [year-to-date map]

The windward coast and upper slope areas, as well as much of the Puna Districts were all above average for July. The rest of the island came in below average, with the Kona and Kohala District coasts faring the worst with totals below around 20% of average, and the rest of the island around 40 to 80% of average. The USGS site at Kawainui Stream had the highest monthly total for the island with 38.09 inches (283% of average), as well as the highest daily total of 4.43 inches on the 7th. The island was also quite divided in terms of statistical extremes. Three sites recorded their wettest July: Kamuela Upper Ua Net (record, since 1992), USGS Kawainui Stream (since 2010), and the HCN climate site at Waiakea Experimental Station (since 2010). In contrast, Kona Airport (since 2003) and the USGS Kilohana RG (since 2013) had the driest July in their respective periods of record.

The year to date (YTD) totals were still mostly near to above average for the island, with a few spots in leeward South Kohala and North Kona Districts below average (60-90%). The highest YTD total was the USGS gage at Honoliʻi Stream with 181.45 inches (137% of average).

Data Sources: Data used in this report are from National Weather Service sources including climate network weather observation stations at Līhuʻe, Honolulu, Kahului, and Hilo, the Ua Net network of automated rain gages, and selected Cooperative Observer sites. Additional data come from automated rain gages operated by the State of Hawaiʻi Department of Land and Natural Resources, the U.S. Geological Survey (USGS), the U.S. Bureau of Land Management, the U.S. National Park Service, the Department of Defense, the U.S. Fish and Wildlife Service, and the U.S. Department of Agriculture, as well as manual observations from the Community Collaborative Rain, Hail, and Snow Network (CoCoRaHS). Averages come from the National Centers for Environmental Information (1991-2020 series) and the Rainfall Atlas of Hawaiʻi (https://www.hawaii.edu/climate-data-portal/hawaii-climate-atlases/). Supplemental data used in some of the analyses are from the Hawaiʻi Climate Data Portal (https://www.hawaii.edu/climate-data-portal/). Data presented here are not certified and should be used for informational purposes only. 

Tina Stall
Senior Service Hydrologist 
NOAA/NWS Weather Forecast Office Honolulu