May is one of the warmer months of the year in Kennewick, with average highs near 22.7°C and lows around 9.2°C (mean 16°C). It is about average for rainfall, averaging 27 mm of rainfall and 53% relative humidity across the period.
May is one of the warmer months of the year in Kennewick. Across 45 years of records, the warmest May in Kennewick was 2018 — when the month averaged 19.4°C — while the coldest was 1984 at 12.9°C. Typical May days reach 22.7°C with nights near 9.2°C. The long-term trend is warming, about 0.3°C per decade.
May is about average for rainfall in Kennewick, averaging 27 mm of rainfall. The wettest May on record was 2022 with 50 mm, while the driest was 1992 at 4 mm.
Relative humidity in Kennewick during May averages 53%. The most humid May was 1998 at 61%, and the least humid was 1992 at 43%.
May receives about 6.4 kWh/m²/day of solar energy in Kennewick. The sunniest May was 2009 at 7.2 kWh/m²/day, and the cloudiest was 1998 at 5.6.
Average wind speed in Kennewick during May is 2.7 m/s. The windiest May was 1998 at 3.1 m/s, while the calmest was 2017 at 2.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 15.3°C | 15.8°C | 16.3°C | 16.4°C | 15.9°C | +0.6°C |
| Avg High | 22.0°C | 22.4°C | 23.1°C | 23.1°C | 22.8°C | +0.8°C |
| Avg Low | 8.5°C | 9.1°C | 9.4°C | 9.7°C | 9.0°C | +0.5°C |
| Avg Rain | 24 mm | 31 mm | 24 mm | 28 mm | 31 mm | +7 mm |
May temperatures in Kennewick have risen by about 0.9°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -0.2°C (1999) to a record high of 38.3°C (1986).
Rainfall in May is about average for rainfall, averaging 27 mm, with a wettest year of 50 mm.
A good time to visit Kennewick
May is a good time to visit Kennewick, with days averaging 22.7°C and nights around 9.2°C (mean 16°C, warmer than Kennewick's yearly average) and low rainfall. August and July 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 | 22.0°C | 14.7°C | 7.4°C | 30.9°C | 1.3°C | 25 mm | 57% | 2.8 m/s | 6.8 |
| 2024 | 21.9°C | 14.8°C | 7.8°C | 31.0°C | 1.6°C | 38 mm | 56% | 2.9 m/s | 6.8 |
| 2023 | 26.2°C | 19.3°C | 12.4°C | 34.4°C | 6.1°C | 16 mm | 52% | 2.4 m/s | 6.8 |
| 2022 🌧️ | 19.4°C | 13.4°C | 7.4°C | 25.6°C | 2.8°C | 50 mm | 59% | 2.7 m/s | 5.9 |
| 2021 | 23.7°C | 16.6°C | 9.5°C | 32.8°C | 4.2°C | 9 mm | 46% | 2.7 m/s | 7.1 |
| 2020 | 23.4°C | 16.5°C | 9.7°C | 34.3°C | 3.4°C | 47 mm | 53% | 2.8 m/s | 6.4 |
| 2019 | 24.2°C | 17.4°C | 10.6°C | 31.4°C | 4.8°C | 26 mm | 53% | 2.6 m/s | 6.4 |
| 2018 🔥 | 26.2°C | 19.4°C | 12.6°C | 32.7°C | 6.2°C | 19 mm | 52% | 2.4 m/s | 6.6 |
| 2017 | 23.3°C | 16.3°C | 9.2°C | 33.2°C | 3.3°C | 19 mm | 55% | 2.3 m/s | 6.6 |
| 2016 | 24.3°C | 17.5°C | 10.8°C | 31.4°C | 6.3°C | 33 mm | 51% | 2.8 m/s | 6.7 |
| 2015 | 25.1°C | 18.2°C | 11.2°C | 33.4°C | 5.3°C | 34 mm | 50% | 2.4 m/s | 6.8 |
| 2014 | 24.0°C | 17.1°C | 10.2°C | 32.0°C | 5.6°C | 13 mm | 51% | 2.7 m/s | 6.8 |
| 2013 | 23.3°C | 16.5°C | 9.7°C | 34.6°C | 0.6°C | 31 mm | 53% | 2.7 m/s | 6.5 |
| 2012 | 21.7°C | 15.1°C | 8.4°C | 33.0°C | 2.3°C | 16 mm | 50% | 2.7 m/s | 6.5 |
| 2011 | 19.5°C | 13.1°C | 6.7°C | 26.4°C | 1.7°C | 48 mm | 58% | 2.7 m/s | 6 |
| 2010 | 19.5°C | 13.4°C | 7.3°C | 29.2°C | 0.8°C | 43 mm | 56% | 2.7 m/s | 5.9 |
| 2009 | 24.1°C | 16.6°C | 9.1°C | 35.7°C | 2.9°C | 22 mm | 49% | 2.7 m/s | 7.2 |
| 2008 | 23.2°C | 16.5°C | 9.7°C | 36.3°C | 2.2°C | 25 mm | 53% | 2.6 m/s | 6.1 |
| 2007 | 24.2°C | 16.6°C | 9.0°C | 33.1°C | 2.7°C | 14 mm | 49% | 2.6 m/s | 7 |
| 2006 | 23.7°C | 16.7°C | 9.7°C | 36.7°C | 1.6°C | 33 mm | 52% | 2.6 m/s | 6.6 |
| 2005 | 23.7°C | 17.2°C | 10.6°C | 34.0°C | 6.1°C | 39 mm | 54% | 2.4 m/s | 6.1 |
| 2004 | 21.7°C | 15.8°C | 9.9°C | 29.3°C | 6.1°C | 31 mm | 55% | 2.8 m/s | 5.9 |
| 2003 | 21.7°C | 15.3°C | 9.0°C | 32.0°C | 2.4°C | 14 mm | 54% | 2.6 m/s | 6.1 |
| 2002 | 21.7°C | 15.1°C | 8.6°C | 28.1°C | 1.1°C | 19 mm | 50% | 2.7 m/s | 6.2 |
| 2001 | 25.2°C | 17.3°C | 9.5°C | 37.5°C | 2.6°C | 8 mm | 45% | 2.5 m/s | 7.1 |
| 2000 | 21.7°C | 15.4°C | 9.2°C | 30.9°C | 2.5°C | 33 mm | 53% | 3 m/s | 6.4 |
| 1999 | 20.4°C | 13.7°C | 7.0°C | 33.6°C | -0.2°C | 21 mm | 52% | 3 m/s | 6.6 |
| 1998 | 20.9°C | 14.9°C | 8.9°C | 31.3°C | 5.9°C | 41 mm | 61% | 3.1 m/s | 5.6 |
| 1997 | 24.1°C | 17.3°C | 10.5°C | 32.6°C | 2.1°C | 21 mm | 57% | 2.4 m/s | 6.5 |
| 1996 | 19.3°C | 13.2°C | 7.1°C | 26.4°C | 1.2°C | 36 mm | 59% | 2.9 m/s | 6.3 |
| 1995 | 23.1°C | 16.5°C | 9.8°C | 32.8°C | 4.5°C | 26 mm | 52% | 2.5 m/s | 6.6 |
| 1994 | 23.7°C | 17.0°C | 10.3°C | 32.0°C | 4.2°C | 45 mm | 53% | 2.5 m/s | 5.9 |
| 1993 | 25.2°C | 18.2°C | 11.2°C | 33.6°C | 4.9°C | 34 mm | 56% | 2.8 m/s | 6.2 |
| 1992 | 26.7°C | 18.8°C | 10.8°C | 35.3°C | 3.7°C | 4 mm | 43% | 2.5 m/s | 7 |
| 1991 | 20.2°C | 13.9°C | 7.6°C | 24.9°C | 2.4°C | 47 mm | 58% | 2.9 m/s | 5.7 |
| 1990 | 20.8°C | 14.5°C | 8.2°C | 32.4°C | 2.6°C | 34 mm | 55% | 2.9 m/s | 5.9 |
| 1989 | 21.8°C | 15.1°C | 8.4°C | 29.4°C | 4.8°C | 30 mm | 56% | 2.7 m/s | 6.2 |
| 1988 | 22.1°C | 15.1°C | 8.0°C | 33.6°C | 1.8°C | 28 mm | 52% | 2.7 m/s | 5.8 |
| 1987 | 24.4°C | 17.4°C | 10.3°C | 35.1°C | 4.8°C | 19 mm | 51% | 2.6 m/s | 6.4 |
| 1986 | 22.1°C | 15.4°C | 8.8°C | 38.3°C | 2.6°C | 28 mm | 57% | 2.6 m/s | 6.2 |
| 1985 | 23.0°C | 15.9°C | 8.7°C | 33.3°C | 1.6°C | 12 mm | 52% | 2.9 m/s | 6.8 |
| 1984 ❄️ | 19.1°C | 12.9°C | 6.8°C | 32.5°C | 2.0°C | 24 mm | 59% | 3 m/s | 5.9 |
| 1983 | 23.6°C | 16.5°C | 9.3°C | 37.1°C | 4.5°C | 25 mm | 56% | 2.6 m/s | — |
| 1982 | 21.1°C | 14.4°C | 7.7°C | 30.3°C | 1.1°C | 14 mm | 53% | 2.6 m/s | — |
| 1981 | 21.2°C | 14.7°C | 8.1°C | 29.0°C | 3.8°C | 38 mm | 55% | 2.6 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 22.7°C with lows near 9.2°C (mean 16°C), based on 45 years of NASA POWER data.
May averages 27 mm of rainfall in Kennewick, about average for rainfall. The wettest on record was 50 mm in 2022.
The hottest May reached 38.3°C in 1986. The coldest dipped to -0.2°C in 1999.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 0.9°C. Daytime highs moved from 21.6°C to 22.6°C and overnight lows from 8.1°C to 8.9°C over the same span.
May is one of the warmer months of the year in Kennewick and about average for rainfall, so plan for around 22.7°C daytime highs and 9.2°C at night.
Not quite — May is the 8th coolest month in Kennewick, averaging 16°C.
For May in Kennewick, pack light layers you can adjust through the day, with typical highs of 22.7°C and lows of 9.2°C.
Relative humidity in May averages 53% — relatively dry.
Average wind speed in May is 2.7 m/s. The windiest May on record averaged 3.1 m/s (1998).
The wettest May on record was 2022 with 50 mm. On average, May sees 27 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 Kennewick 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.
