May is one of the warmer months of the year in Bellingham, with average highs near 16.5°C and lows around 7.7°C (mean 12.1°C). It is one of the drier months, averaging 77 mm of rainfall and 79% relative humidity across the period.
May is one of the warmer months of the year in Bellingham. Across 45 years of records, the warmest May in Bellingham was 2023 — when the month averaged 14.8°C — while the coldest was 1999 at 9.6°C. Typical May days reach 16.5°C with nights near 7.7°C. The long-term trend is warming, about 0.2°C per decade.
May is one of the drier months in Bellingham, averaging 77 mm of rainfall. The wettest May on record was 1984 with 153 mm, while the driest was 2018 at 14 mm.
Relative humidity in Bellingham during May averages 79%. The most humid May was 2025 at 84%, and the least humid was 1992 at 72%.
May receives about 5.5 kWh/m²/day of solar energy in Bellingham. The sunniest May was 1995 at 6.5 kWh/m²/day, and the cloudiest was 1988 at 4.7.
Average wind speed in Bellingham during May is 0.5 m/s. The windiest Mays were 2022, 2024 and 2025, among others at 0.6 m/s, while the calmest were 2020, 2021 and 2023, among others at 0.5 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 11.6°C | 12.3°C | 11.8°C | 12.6°C | 11.9°C | +0.3°C |
| Avg High | 16.1°C | 16.8°C | 16.2°C | 17.1°C | 16.2°C | +0.1°C |
| Avg Low | 7.2°C | 7.9°C | 7.4°C | 8.3°C | 7.8°C | +0.6°C |
| Avg Rain | 89 mm | 71 mm | 75 mm | 68 mm | 84 mm | -4 mm |
May temperatures in Bellingham have stayed relatively stable across the record.
May has ranged from a record low of 0.6°C (1999) to a record high of 34.4°C (1983).
Rainfall in May is one of the drier months, averaging 77 mm, with a wettest year of 153 mm.
A good time to visit Bellingham
May is a good time to visit Bellingham, with days averaging 16.5°C and nights around 7.7°C (mean 12.1°C, warmer than Bellingham's yearly average) and moderate 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 | 14.5°C | 10.6°C | 6.6°C | 24.8°C | 3.8°C | 86 mm | 84% | 0.6 m/s | 5.9 |
| 2024 | 15.4°C | 11.2°C | 7.1°C | 24.3°C | 2.7°C | 92 mm | 83% | 0.6 m/s | 5.6 |
| 2023 🔥 | 19.5°C | 14.8°C | 10.2°C | 32.0°C | 5.7°C | 46 mm | 79% | 0.5 m/s | 6.3 |
| 2022 | 13.8°C | 10.2°C | 6.6°C | 20.5°C | 3.5°C | 118 mm | 83% | 0.6 m/s | 4.8 |
| 2021 | 15.9°C | 11.7°C | 7.6°C | 23.8°C | 4.8°C | 51 mm | 78% | 0.5 m/s | 5.9 |
| 2020 | 17.8°C | 13.1°C | 8.5°C | 28.5°C | 2.4°C | 114 mm | 78% | 0.5 m/s | 5.6 |
| 2019 | 19.2°C | 14.5°C | 9.8°C | 25.4°C | 4.9°C | 47 mm | 78% | 0.5 m/s | 5.9 |
| 2018 | 19.1°C | 14.3°C | 9.6°C | 27.5°C | 5.2°C | 14 mm | 79% | 0.5 m/s | 6.4 |
| 2017 | 17.2°C | 12.6°C | 8.1°C | 27.6°C | 4.3°C | 83 mm | 78% | 0.5 m/s | 5.6 |
| 2016 | 18.3°C | 13.9°C | 9.5°C | 28.4°C | 6.4°C | 51 mm | 77% | 0.5 m/s | 5.7 |
| 2015 | 18.7°C | 14.2°C | 9.7°C | 27.4°C | 4.9°C | 25 mm | 79% | 0.5 m/s | 5.9 |
| 2014 | 17.1°C | 13.0°C | 8.9°C | 27.1°C | 4.8°C | 92 mm | 81% | 0.5 m/s | 5.5 |
| 2013 | 17.1°C | 12.7°C | 8.3°C | 28.3°C | 1.1°C | 83 mm | 79% | 0.5 m/s | 5.2 |
| 2012 | 15.7°C | 11.0°C | 6.3°C | 23.9°C | 2.2°C | 68 mm | 76% | 0.6 m/s | 5.7 |
| 2011 | 13.6°C | 9.7°C | 5.9°C | 19.5°C | 2.8°C | 122 mm | 83% | 0.5 m/s | 4.9 |
| 2010 | 14.6°C | 10.5°C | 6.5°C | 21.4°C | 1.8°C | 99 mm | 79% | 0.6 m/s | 5.1 |
| 2009 | 16.3°C | 11.5°C | 6.7°C | 23.5°C | 3.2°C | 97 mm | 77% | 0.5 m/s | 5.9 |
| 2008 | 16.7°C | 12.0°C | 7.4°C | 29.2°C | 2.5°C | 56 mm | 79% | 0.5 m/s | 4.9 |
| 2007 | 16.1°C | 11.6°C | 7.0°C | 26.1°C | 3.5°C | 47 mm | 78% | 0.5 m/s | 5.9 |
| 2006 | 17.2°C | 12.4°C | 7.6°C | 31.4°C | 2.7°C | 72 mm | 76% | 0.6 m/s | 5.7 |
| 2005 | 18.5°C | 13.9°C | 9.3°C | 32.2°C | 6.1°C | 67 mm | 79% | 0.5 m/s | 5.3 |
| 2004 | 16.8°C | 12.8°C | 8.7°C | 24.1°C | 4.8°C | 83 mm | 79% | 0.5 m/s | 5.2 |
| 2003 | 15.4°C | 11.3°C | 7.2°C | 24.0°C | 2.9°C | 58 mm | 79% | 0.5 m/s | 5.3 |
| 2002 | 14.4°C | 10.2°C | 6.1°C | 24.6°C | 1.5°C | 66 mm | 80% | 0.6 m/s | 5.3 |
| 2001 | 15.8°C | 11.3°C | 6.9°C | 28.8°C | 1.8°C | 73 mm | 76% | 0.6 m/s | 5.6 |
| 2000 | 14.5°C | 10.7°C | 6.9°C | 20.3°C | 2.0°C | 127 mm | 82% | 0.5 m/s | 4.9 |
| 1999 ❄️ | 13.9°C | 9.6°C | 5.2°C | 28.1°C | 0.6°C | 77 mm | 79% | 0.6 m/s | 5.7 |
| 1998 | 16.2°C | 12.2°C | 8.2°C | 29.1°C | 4.4°C | 94 mm | 82% | 0.5 m/s | 5.1 |
| 1997 | 18.6°C | 13.9°C | 9.1°C | 30.2°C | 1.5°C | 104 mm | 78% | 0.5 m/s | 5.5 |
| 1996 | 13.9°C | 10.1°C | 6.4°C | 19.3°C | 2.6°C | 103 mm | 80% | 0.6 m/s | 5.4 |
| 1995 | 18.8°C | 13.7°C | 8.7°C | 25.3°C | 5.3°C | 31 mm | 74% | 0.5 m/s | 6.5 |
| 1994 | 17.2°C | 12.6°C | 8.0°C | 22.8°C | 3.1°C | 41 mm | 77% | 0.6 m/s | 5.8 |
| 1993 | 19.2°C | 14.4°C | 9.7°C | 33.5°C | 3.7°C | 109 mm | 79% | 0.5 m/s | 5.3 |
| 1992 | 18.9°C | 13.8°C | 8.7°C | 27.7°C | 3.2°C | 23 mm | 72% | 0.5 m/s | 6.1 |
| 1991 | 15.3°C | 11.3°C | 7.4°C | 20.9°C | 4.3°C | 64 mm | 81% | 0.5 m/s | 5.1 |
| 1990 | 15.7°C | 11.6°C | 7.4°C | 22.4°C | 3.7°C | 61 mm | 80% | 0.6 m/s | 5.3 |
| 1989 | 16.1°C | 11.7°C | 7.2°C | 23.1°C | 3.9°C | 94 mm | 79% | 0.6 m/s | 5.4 |
| 1988 | 16.1°C | 11.4°C | 6.8°C | 29.0°C | 3.1°C | 126 mm | 79% | 0.6 m/s | 4.7 |
| 1987 | 17.0°C | 12.2°C | 7.5°C | 25.8°C | 3.7°C | 100 mm | 77% | 0.6 m/s | 6 |
| 1986 | 15.7°C | 11.5°C | 7.3°C | 28.8°C | 2.7°C | 117 mm | 79% | 0.6 m/s | 5 |
| 1985 | 16.3°C | 11.8°C | 7.4°C | 29.0°C | 2.0°C | 62 mm | 77% | 0.5 m/s | 5.4 |
| 1984 🌧️ | 13.4°C | 9.7°C | 5.9°C | 21.6°C | 3.6°C | 153 mm | 81% | 0.6 m/s | 5.1 |
| 1983 | 18.3°C | 13.4°C | 8.5°C | 34.4°C | 4.8°C | 46 mm | 77% | 0.5 m/s | — |
| 1982 | 16.0°C | 11.4°C | 6.8°C | 23.5°C | 2.1°C | 30 mm | 75% | 0.5 m/s | — |
| 1981 | 15.8°C | 11.6°C | 7.4°C | 24.2°C | 2.9°C | 73 mm | 79% | 0.5 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 16.5°C with lows near 7.7°C (mean 12.1°C), based on 45 years of NASA POWER data.
May averages 77 mm of rainfall in Bellingham, one of the drier months. The wettest on record was 153 mm in 1984.
The hottest May reached 34.4°C in 1983. The coldest dipped to 0.6°C in 1999.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 0.1°C — but days and nights have moved in opposite directions. Overnight lows rose from 7.2°C to 7.6°C while daytime highs eased from 16°C to 15.8°C, narrowing the gap between day and night.
May is one of the warmer months of the year in Bellingham and one of the drier months, so plan for around 16.5°C daytime highs and 7.7°C at night.
Not quite — May is the 8th coolest month in Bellingham, averaging 12.1°C.
For May in Bellingham, pack warm layers and a jacket for chilly mornings, with typical highs of 16.5°C and lows of 7.7°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 79% — quite humid.
Average wind speed in May is 0.5 m/s. The windiest May on record averaged 0.6 m/s (1984).
The wettest May on record was 1984 with 153 mm. On average, May sees 77 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 Bellingham 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.
