May is close to Waipahu's year-round average, with average highs near 25.9°C and lows around 22.8°C (mean 24.4°C). It is one of the drier months, averaging 41 mm of rainfall and 74% relative humidity across the period.
May is close to Waipahu's year-round average. Across 45 years of records, the warmest May in Waipahu was 2025 — when the month averaged 25.7°C — while the coldest was 1985 at 22.5°C. Typical May days reach 25.9°C with nights near 22.8°C. The long-term trend is warming, about 0.4°C per decade.
May is one of the drier months in Waipahu, averaging 41 mm of rainfall. The wettest May on record was 2002 with 129 mm, while the driest was 1996 at 5 mm.
Relative humidity in Waipahu during May averages 74%. The most humid May was 2002 at 81%, and the least humid was 2008 at 70%.
May receives about 6.8 kWh/m²/day of solar energy in Waipahu. The sunniest May was 2020 at 7.4 kWh/m²/day, and the cloudiest was 2018 at 6.
Average wind speed in Waipahu during May is 5.4 m/s. The windiest May was 1998 at 7.6 m/s, while the calmest was 2009 at 2.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 23.5°C | 24.0°C | 24.7°C | 24.7°C | 25.0°C | +1.5°C |
| Avg High | 25.0°C | 25.5°C | 26.3°C | 26.2°C | 26.5°C | +1.5°C |
| Avg Low | 22.0°C | 22.4°C | 23.0°C | 23.1°C | 23.4°C | +1.4°C |
| Avg Rain | 50 mm | 25 mm | 36 mm | 52 mm | 44 mm | -6 mm |
May temperatures in Waipahu have risen by about 1.6°C between 1981–1985 and 2021–2025.
May has ranged from a record low of 18.7°C (1987) to a record high of 28.9°C (2009).
Rainfall in May is one of the drier months, averaging 41 mm, with a wettest year of 129 mm.
A good time to visit Waipahu
May is a good time to visit Waipahu, with days averaging 25.9°C and nights around 22.8°C (mean 24.4°C, close to Waipahu's yearly average) and moderate rainfall. February and March are marginally more temperate, but May still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 🔥 | 27.3°C | 25.7°C | 24.1°C | 28.0°C | 23.2°C | 15 mm | 72% | 6.5 m/s | 7.3 |
| 2024 | 26.5°C | 24.9°C | 23.4°C | 27.5°C | 22.2°C | 53 mm | 76% | 5 m/s | 6.6 |
| 2023 | 26.3°C | 24.7°C | 23.1°C | 27.7°C | 21.8°C | 31 mm | 75% | 5.4 m/s | 6.8 |
| 2022 | 26.3°C | 24.8°C | 23.3°C | 27.8°C | 22.6°C | 74 mm | 76% | 5.6 m/s | 6.8 |
| 2021 | 26.4°C | 24.8°C | 23.3°C | 28.3°C | 22.6°C | 38 mm | 75% | 5.4 m/s | 7.3 |
| 2020 | 26.4°C | 24.8°C | 23.3°C | 27.5°C | 22.3°C | 55 mm | 76% | 5.5 m/s | 7.4 |
| 2019 | 26.8°C | 25.1°C | 23.4°C | 28.5°C | 20.5°C | 66 mm | 76% | 4.1 m/s | 7 |
| 2018 | 25.4°C | 24.1°C | 22.8°C | 26.7°C | 20.7°C | 50 mm | 79% | 5.5 m/s | 6 |
| 2017 | 26.9°C | 25.2°C | 23.6°C | 27.8°C | 22.2°C | 42 mm | 75% | 4.9 m/s | 7.3 |
| 2016 | 26.5°C | 25.0°C | 23.4°C | 27.9°C | 22.0°C | 71 mm | 75% | 5 m/s | 7 |
| 2015 | 25.7°C | 24.2°C | 22.6°C | 26.8°C | 21.4°C | 44 mm | 74% | 5.7 m/s | 7 |
| 2014 | 26.6°C | 25.0°C | 23.4°C | 27.8°C | 21.5°C | 83 mm | 75% | 3.4 m/s | 6.5 |
| 2013 | 26.5°C | 24.9°C | 23.2°C | 28.2°C | 21.9°C | 50 mm | 73% | 4.4 m/s | 7.1 |
| 2012 | 25.7°C | 24.1°C | 22.5°C | 26.9°C | 21.1°C | 12 mm | 72% | 6.5 m/s | 7.3 |
| 2011 | 26.0°C | 24.6°C | 23.3°C | 26.8°C | 22.6°C | 78 mm | 76% | 5.9 m/s | 6.3 |
| 2010 | 26.3°C | 24.7°C | 23.2°C | 27.0°C | 22.6°C | 22 mm | 72% | 6 m/s | 6.9 |
| 2009 | 26.6°C | 24.7°C | 22.8°C | 28.9°C | 21.1°C | 16 mm | 71% | 2.8 m/s | 7.2 |
| 2008 | 26.7°C | 25.0°C | 23.3°C | 28.2°C | 22.6°C | 15 mm | 70% | 5.2 m/s | 7.1 |
| 2007 | 26.8°C | 25.1°C | 23.3°C | 28.3°C | 22.7°C | 7 mm | 70% | 5.4 m/s | 7.2 |
| 2006 | 25.1°C | 23.6°C | 22.1°C | 27.2°C | 20.1°C | 33 mm | 75% | 5.7 m/s | 7.3 |
| 2005 | 26.8°C | 25.2°C | 23.6°C | 27.7°C | 22.8°C | 39 mm | 76% | 5.4 m/s | 7.1 |
| 2004 | 26.4°C | 24.9°C | 23.4°C | 28.1°C | 21.7°C | 90 mm | 77% | 5.1 m/s | 6.9 |
| 2003 | 26.8°C | 25.0°C | 23.2°C | 28.3°C | 22.6°C | 16 mm | 72% | 5.5 m/s | 7.1 |
| 2002 🌧️ | 25.9°C | 24.6°C | 23.3°C | 28.1°C | 22.5°C | 129 mm | 81% | 4.5 m/s | 6.1 |
| 2001 | 26.3°C | 24.5°C | 22.7°C | 28.1°C | 21.6°C | 14 mm | 72% | 5.3 m/s | 7.2 |
| 2000 | 25.8°C | 24.1°C | 22.4°C | 26.5°C | 21.6°C | 7 mm | 73% | 5.9 m/s | 7.1 |
| 1999 | 26.0°C | 24.4°C | 22.8°C | 27.0°C | 22.0°C | 30 mm | 72% | 4.7 m/s | 6.6 |
| 1998 | 24.3°C | 23.1°C | 21.8°C | 25.4°C | 21.2°C | 30 mm | 73% | 7.6 m/s | 6.5 |
| 1997 | 25.1°C | 23.5°C | 21.9°C | 27.1°C | 20.8°C | 72 mm | 73% | 5.3 m/s | 6.8 |
| 1996 | 26.7°C | 24.9°C | 23.2°C | 28.6°C | 20.2°C | 5 mm | 72% | 4.8 m/s | 7 |
| 1995 | 25.5°C | 23.9°C | 22.2°C | 27.3°C | 20.3°C | 7 mm | 72% | 5.7 m/s | 6.8 |
| 1994 | 25.8°C | 24.2°C | 22.7°C | 26.5°C | 21.8°C | 15 mm | 72% | 6.4 m/s | 6.4 |
| 1993 | 25.5°C | 23.9°C | 22.3°C | 26.7°C | 21.3°C | 13 mm | 71% | 6 m/s | 6.8 |
| 1992 | 26.2°C | 24.5°C | 22.8°C | 28.7°C | 20.6°C | 15 mm | 72% | 4.2 m/s | 6.3 |
| 1991 | 25.5°C | 24.0°C | 22.5°C | 27.2°C | 21.0°C | 18 mm | 73% | 5.6 m/s | 6.5 |
| 1990 | 24.8°C | 23.4°C | 21.9°C | 25.9°C | 20.8°C | 50 mm | 76% | 6.6 m/s | 6.5 |
| 1989 | 25.2°C | 23.7°C | 22.2°C | 26.6°C | 19.5°C | 74 mm | 76% | 5.9 m/s | 6.4 |
| 1988 | 25.7°C | 24.3°C | 22.9°C | 27.0°C | 21.1°C | 34 mm | 77% | 5.8 m/s | 6.4 |
| 1987 | 24.4°C | 22.8°C | 21.2°C | 27.2°C | 18.7°C | 38 mm | 74% | 4.9 m/s | 6.5 |
| 1986 | 25.2°C | 23.8°C | 22.5°C | 26.9°C | 20.9°C | 42 mm | 78% | 4.8 m/s | 6.1 |
| 1985 ❄️ | 23.8°C | 22.5°C | 21.2°C | 25.2°C | 19.5°C | 89 mm | 79% | 6 m/s | 6.1 |
| 1984 | 25.6°C | 24.1°C | 22.6°C | 26.9°C | 21.7°C | 37 mm | 76% | 5.6 m/s | 6.9 |
| 1983 | 24.2°C | 22.8°C | 21.4°C | 25.4°C | 19.8°C | 41 mm | 77% | 5.5 m/s | — |
| 1982 | 24.6°C | 23.2°C | 21.8°C | 25.8°C | 20.7°C | 76 mm | 79% | 5 m/s | — |
| 1981 | 25.9°C | 24.2°C | 22.5°C | 27.2°C | 20.6°C | 22 mm | 73% | 5.3 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 25.9°C with lows near 22.8°C (mean 24.4°C), based on 45 years of NASA POWER data.
May averages 41 mm of rainfall in Waipahu, one of the drier months. The wettest on record was 129 mm in 2002.
The hottest May reached 28.9°C in 2009. The coldest dipped to 18.7°C in 1987.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 1.6°C. Daytime highs moved from 24.8°C to 26.6°C and overnight lows from 21.9°C to 23.4°C over the same span.
May is close to Waipahu's year-round average and one of the drier months, so plan for around 25.9°C daytime highs and 22.8°C at night.
Not quite — May is the 6th coolest month in Waipahu, averaging 24.4°C.
For May in Waipahu, pack light layers you can adjust through the day, with typical highs of 25.9°C and lows of 22.8°C.
Relative humidity in May averages 74% — moderately humid.
Average wind speed in May is 5.4 m/s. The windiest May on record averaged 7.6 m/s (1998).
The wettest May on record was 2002 with 129 mm. On average, May sees 41 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Waipahu behaves each May, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for May specifically, along with year-by-year records and how the month has changed over the decades.
