May is one of the warmer months of the year in Grand Junction, with average highs near 21.3°C and lows around 5.5°C (mean 13.4°C). It is about average for rainfall, averaging 33 mm of rainfall and 44% relative humidity across the period.
May is one of the warmer months of the year in Grand Junction. Across 45 years of records, the warmest May in Grand Junction was 2018 — when the month averaged 16.2°C — while the coldest was 1995 at 10.1°C. Typical May days reach 21.3°C with nights near 5.5°C. The long-term trend is warming, about 0.2°C per decade.
May is about average for rainfall in Grand Junction, averaging 33 mm of rainfall. The wettest May on record was 1995 with 95 mm, while the driest was 2012 at 3 mm.
Relative humidity in Grand Junction during May averages 44%. The most humid May was 1995 at 59%, and the least humid was 2002 at 27%.
May receives about 7 kWh/m²/day of solar energy in Grand Junction. The sunniest Mays were 2012 and 2020 at 7.6 kWh/m²/day, and the cloudiest was 1995 at 5.7.
Average wind speed in Grand Junction during May is 2.6 m/s. The windiest May was 1991 at 3.3 m/s, while the calmest was 1992 at 2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 12.8°C | 13.1°C | 14.5°C | 12.8°C | 14.3°C | +1.5°C |
| Avg High | 20.6°C | 20.9°C | 22.6°C | 20.6°C | 22.5°C | +1.9°C |
| Avg Low | 5.1°C | 5.3°C | 6.4°C | 5.0°C | 6.1°C | +1°C |
| Avg Rain | 36 mm | 41 mm | 27 mm | 37 mm | 17 mm | -19 mm |
May temperatures in Grand Junction have risen by about 1.4°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -5.8°C (2013) to a record high of 36°C (2002).
Rainfall in May is about average for rainfall, averaging 33 mm, with a wettest year of 95 mm.
A good time to visit Grand Junction
May is a good time to visit Grand Junction, with days averaging 21.3°C and nights around 5.5°C (mean 13.4°C, warmer than Grand Junction's yearly average) and moderate rainfall. August and June 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 | 23.1°C | 14.9°C | 6.7°C | 33.1°C | 0.6°C | 17 mm | 40% | 2.3 m/s | 7.2 |
| 2024 | 20.7°C | 12.5°C | 4.3°C | 29.5°C | -3.7°C | 26 mm | 44% | 2.7 m/s | 6.7 |
| 2023 | 22.3°C | 14.7°C | 7.0°C | 26.9°C | 1.8°C | 13 mm | 50% | 2.2 m/s | 6.9 |
| 2022 | 21.5°C | 13.3°C | 5.1°C | 30.2°C | -1.7°C | 17 mm | 37% | 2.9 m/s | 6.9 |
| 2021 | 22.7°C | 14.4°C | 6.1°C | 28.8°C | -0.3°C | 21 mm | 37% | 2.6 m/s | 7.1 |
| 2020 | 24.4°C | 15.8°C | 7.1°C | 33.4°C | 0.0°C | 8 mm | 36% | 2.9 m/s | 7.6 |
| 2019 | 17.2°C | 10.3°C | 3.4°C | 25.9°C | -1.3°C | 55 mm | 54% | 2.4 m/s | 6.4 |
| 2018 🔥 | 24.5°C | 16.2°C | 7.9°C | 30.0°C | 1.5°C | 11 mm | 35% | 2.7 m/s | 7.1 |
| 2017 | 21.3°C | 13.3°C | 5.3°C | 28.2°C | -1.8°C | 32 mm | 46% | 2.4 m/s | 6.8 |
| 2016 | 20.1°C | 12.4°C | 4.7°C | 26.6°C | -1.6°C | 41 mm | 49% | 2.4 m/s | 6.8 |
| 2015 | 18.5°C | 11.8°C | 5.1°C | 28.7°C | -0.2°C | 82 mm | 58% | 2.3 m/s | 5.8 |
| 2014 | 21.5°C | 13.5°C | 5.5°C | 31.3°C | -4.8°C | 48 mm | 44% | 2.8 m/s | 6.7 |
| 2013 | 21.4°C | 13.4°C | 5.4°C | 28.4°C | -5.8°C | 29 mm | 42% | 2.7 m/s | 7.1 |
| 2012 | 24.5°C | 15.8°C | 7.2°C | 31.3°C | 1.4°C | 3 mm | 28% | 3 m/s | 7.6 |
| 2011 | 17.9°C | 10.3°C | 2.8°C | 24.7°C | -5.6°C | 45 mm | 49% | 3 m/s | 6.4 |
| 2010 | 18.7°C | 10.6°C | 2.5°C | 29.0°C | -4.3°C | 22 mm | 44% | 3.1 m/s | 7 |
| 2009 | 22.3°C | 15.0°C | 7.7°C | 30.8°C | 2.6°C | 52 mm | 46% | 2.1 m/s | 6.8 |
| 2008 | 19.5°C | 11.4°C | 3.4°C | 29.4°C | -4.7°C | 34 mm | 46% | 2.7 m/s | 6.9 |
| 2007 | 22.1°C | 14.1°C | 6.2°C | 28.6°C | -2.0°C | 25 mm | 45% | 2.4 m/s | 6.7 |
| 2006 | 24.2°C | 15.7°C | 7.3°C | 30.8°C | -0.3°C | 10 mm | 36% | 2.3 m/s | 7.5 |
| 2005 | 21.3°C | 13.6°C | 5.8°C | 30.8°C | -0.6°C | 20 mm | 49% | 2.4 m/s | 7.1 |
| 2004 | 22.9°C | 14.6°C | 6.4°C | 27.5°C | 0.2°C | 14 mm | 38% | 2.9 m/s | 7.3 |
| 2003 | 22.7°C | 14.6°C | 6.6°C | 32.9°C | -0.8°C | 46 mm | 45% | 2.4 m/s | 6.8 |
| 2002 | 23.6°C | 14.9°C | 6.2°C | 36.0°C | -1.1°C | 8 mm | 27% | 2.7 m/s | 7.5 |
| 2001 | 23.5°C | 15.2°C | 6.9°C | 30.3°C | -2.4°C | 35 mm | 42% | 2.2 m/s | 7.1 |
| 2000 | 24.2°C | 15.8°C | 7.4°C | 33.7°C | -1.1°C | 23 mm | 37% | 2.9 m/s | 7.2 |
| 1999 | 19.7°C | 11.7°C | 3.7°C | 29.0°C | -5.3°C | 28 mm | 46% | 2.7 m/s | 6.9 |
| 1998 | 20.9°C | 13.1°C | 5.4°C | 26.5°C | -0.5°C | 19 mm | 44% | 2.9 m/s | 7.4 |
| 1997 | 21.6°C | 13.8°C | 6.0°C | 30.6°C | -5.3°C | 52 mm | 51% | 2.1 m/s | 7.1 |
| 1996 | 22.9°C | 14.7°C | 6.4°C | 29.0°C | 1.6°C | 24 mm | 39% | 2.8 m/s | 7.1 |
| 1995 ❄️ 🌧️ | 16.9°C | 10.1°C | 3.3°C | 22.5°C | -1.6°C | 95 mm | 59% | 2.3 m/s | 5.7 |
| 1994 | 22.8°C | 14.5°C | 6.2°C | 29.7°C | 1.8°C | 17 mm | 44% | 2.5 m/s | 7 |
| 1993 | 20.5°C | 13.0°C | 5.5°C | 28.3°C | -2.8°C | 66 mm | 56% | 2.2 m/s | 6.8 |
| 1992 | 21.7°C | 14.4°C | 7.2°C | 27.1°C | 0.3°C | 83 mm | 54% | 2 m/s | 6.9 |
| 1991 | 20.9°C | 12.8°C | 4.7°C | 26.6°C | -1.8°C | 12 mm | 43% | 3.3 m/s | 6.8 |
| 1990 | 20.9°C | 12.6°C | 4.4°C | 27.9°C | -2.4°C | 13 mm | 40% | 3 m/s | 7.1 |
| 1989 | 22.5°C | 14.3°C | 6.2°C | 29.9°C | 0.9°C | 10 mm | 36% | 2.9 m/s | 7.3 |
| 1988 | 20.6°C | 12.7°C | 4.7°C | 28.3°C | -2.9°C | 37 mm | 43% | 2.9 m/s | 7.3 |
| 1987 | 20.2°C | 13.2°C | 6.3°C | 25.9°C | -0.4°C | 48 mm | 54% | 2.4 m/s | 6.4 |
| 1986 | 20.0°C | 11.8°C | 3.7°C | 27.5°C | -2.1°C | 40 mm | 47% | 2.8 m/s | 7.2 |
| 1985 | 21.2°C | 13.7°C | 6.1°C | 26.2°C | -2.7°C | 39 mm | 46% | 2.5 m/s | 6.7 |
| 1984 | 22.8°C | 14.4°C | 6.1°C | 31.1°C | -4.9°C | 21 mm | 45% | 2.7 m/s | 7.2 |
| 1983 | 17.7°C | 10.2°C | 2.8°C | 28.5°C | -2.8°C | 55 mm | 54% | 2.5 m/s | — |
| 1982 | 20.0°C | 12.4°C | 4.8°C | 27.0°C | -0.4°C | 26 mm | 45% | 2.7 m/s | — |
| 1981 | 20.1°C | 12.5°C | 4.9°C | 27.9°C | -2.1°C | 47 mm | 45% | 2.8 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 21.3°C with lows near 5.5°C (mean 13.4°C), based on 45 years of NASA POWER data.
May averages 33 mm of rainfall in Grand Junction, about average for rainfall. The wettest on record was 95 mm in 1995.
The hottest May reached 36°C in 2002. The coldest dipped to -5.8°C in 2013.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 1.4°C. Daytime highs moved from 20.4°C to 22.1°C and overnight lows from 4.9°C to 5.8°C over the same span.
May is one of the warmer months of the year in Grand Junction and about average for rainfall, so plan for around 21.3°C daytime highs and 5.5°C at night.
Not quite — May is the 8th coolest month in Grand Junction, averaging 13.4°C.
For May in Grand Junction, pack warm layers and a jacket for chilly mornings, with typical highs of 21.3°C and lows of 5.5°C.
Relative humidity in May averages 44% — relatively dry.
Average wind speed in May is 2.6 m/s. The windiest May on record averaged 3.3 m/s (1991).
The wettest May on record was 1995 with 95 mm. On average, May sees 33 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 Grand Junction 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.
