April 2026 Monthly Rainfall Summary for Hawaii

Monthly Precipitation Summary

State of Hawaii

Month: April 2026

Prepared: May 6, 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: Active first half of the month, followed by drier conditions and an eventual return to typical trade wind weather.

April began with generally dry and stable conditions as surface high pressure far north of the state shifted eastward. Trade winds gradually eased through the 5th, while below-average moisture kept rainfall minimal statewide.

A more active pattern developed beginning on the 6th as a deepening upper-level trough moved to the northwest of Kauaʻi and increased instability across the islands. At the same time, a cold front approached from the west and a surface trough developed ahead of it, shifting winds from the southeast to southerly and drawing deep tropical moisture northward. This setup produced several days of unsettled weather with intermittent heavy rain and isolated thunderstorms through the 13th. The heaviest rainfall initially affected the Big Island on the 7th and 8th under pre-frontal southeast flow. As the weakening front moved eastward down the island chain, the focus of heaviest rainfall shifted to Kauaʻi, Oʻahu, and Maui County from the 9th through the 11th. Another upper-level disturbance moving through on the 11th into the 12th triggered an additional round of heavy showers and thunderstorms over the western and central islands. Flooding and landslides led to multiple road closures, particularly on Kauaʻi, Oʻahu, and the southeast slopes of the Big Island.

Low pressure lingered north of the state, with light and variable winds through the 16th. After a brief return of moderate trades on the 17th and 18th, winds weakened again by the 19th as another surface trough developed northwest of Kauaʻi. An upper-level disturbance moving through the region provided enough instability to trigger thunderstorms through the 20th, though most of the activity remained north of the islands and over interior and southeast portions of the Big Island. Periods of enhanced showers also developed over the Koʻolau Mountains and central areas of Oʻahu and Kauaʻi during this period. Light and variable winds with land and sea breezes prevailed through the 23rd as the surface low lingered north of the state.

A more typical trade wind pattern returned late in the month as a surface ridge rebuilt north of the islands. Moderate to locally breezy trades developed by the 24th, though rainfall remained limited through the 25th due to lingering upper-level stability. Windward and mauka showers increased slightly through the end of the month, but overall rainfall totals remained light.

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

Very similar to March, all but three of the reporting sites on Kauaʻi came in above average for April, with most amounting to two to four times their April averages. The three below-average sites were located along the northern coast of the island (NWS Ua Net sites at Hanalei, Wainiha and Kilohana), which was in the rain shadow under the dominant south/southwest flow during the bulk of the rainfall this month. The USGS gage on Mt. Waiʻaleʻale had the highest monthly total for the island and the state with 30.04 inches (80% of average), as well as the highest daily total for the island and the state with 15.00 inches on the 9th. The Līhuʻe Airport (period of record since 1950) broke two daily rainfall records during the month: 2.45 inches on 4/9 (old record 1.00 inch in 1959) and 0.85 inches on 4/10 (old record 0.70 inches in 2001). In addition, two sites had their wettest April: Mākaha Ridge RAWS (since 2016) and Puʻu ʻŌpae RAWS (wettest in its period of record – since 2010 – with the caveat of missing data in April 2017).

The year to date (YTD) totals and percentages of average were all near to above average. Higher rainfall in January and February along the northern portion of the island kept those areas just above normal, despite below average March and April rainfall. The highest YTD total still belongs to Mt. Waiʻaleʻale with 158.75 inches (127% of average).

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

The majority of the island came in above average again for April, though not quite as spectacularly so as in March. The rainfall this month was somewhat less widespread as well, resulting in a few spots recording slightly below average rainfall for the month. The sites farthest above average (200 to 400%) were located along the normally-drier leeward areas from Kaʻena Point to Hawaiʻi Kai due to the dominant southerly flow associated with the bulk of the rainfall in early to mid-April. The USGS Moanalua RG site had the highest total for the month with 10.48 inches, (97% of average). The highest daily total went to the Kuaokalā RAWS with 7.75 inches on the 10th. The Honolulu Airport (period of record since 1940) set two daily rainfall records during April: 1.10” on 4/7 (tied record set in 1948), 0.94 inches on 4/10 (old record 0.82 inches in 1963). The NWS Waiʻanae Boat Harbor (since 2004) and the USGS Mākaha Stream (since 2008, with the caveat of missing data in April 2020) rain gages had their wettest April in their respective periods of record. The Mākua Range and Schofield Barracks RAWS sites had their wettest April since 2013 and 2007, respectively. The Hawaiʻi Kai Golf Course had its wettest April since 1963 and the 3rd wettest April on record (since 1908) for that site.

The year to date (YTD) totals continue to run well above average (generally 100-300%). The highest YTD total came from the USGS Moanalua RG (102.84 inches, 218% of average).

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

Most sites across the county came in above average. The small subset of below average sites varied widely in their percentages, but were mainly situated along the northern coasts of Molokaʻi and Maui and included a few of the usual top performers like Puʻu Kukui and West Wailuaiki Stream, which only received 30 to 40% of their April averages. The NWS gage at Hāna Airport took the top spot for monthly total in the county with 18.61 inches (372% of average), as well as the highest daily total of 10.40 inches on the 7th. This site also recorded its wettest April since 2013. Despite being located in an area largely missed by the big April rainfall, the Kahului Airport managed to set a daily rainfall record on April 12 with 0.71 inches (old record 0.53 inches in 2020).

The year to date (YTD) totals for all reporting sites in the county were near to above average (around 100 to 300%). The highest YTD total was at Puʻu Kukui with 133.26 inches. This amount is only 99% of average for the year, though, due to its atypically-low April total.

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

April brought a mixed bag for the island, with widely-varying percentages of average. The highest rainfall totals and highest above average were in the Kaʻu and Puna Districts, as well as portions of the lower Kona District slopes. Despite receiving some good windward rainfall late in the month, most spots in the Hāmākua and Hilo Districts only had around 30 to 70% of their April averages. The Kealakomo RAWS had the highest monthly total with 18.79 inches (408% of average), as well as the highest daily total of 11.46 inches on the 8th. This site also had its wettest April on record (since 2010). The NWS Ua Net site at Pāhala recorded its wettest April on record (since 1991, with the caveat of missing data in April 2015). The Kapāpala and Nene Cabin RAWS sites also had their wettest April in a decade (since 2016 and 2015, respectively).

The year to date (YTD) totals were all still near to above average for the island. The highest YTD total goes to the USGS gage at Honoliʻi Stream with 90.42 inches (114% 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