May is one of the warmer months of the year in Greeley, with average highs near 21.1°C and lows around 5.6°C (mean 13.4°C). It is a relatively wet time of year, averaging 68 mm of rainfall and 51% relative humidity across the period.
May is one of the warmer months of the year in Greeley. Across 45 years of records, the warmest May in Greeley was 1994 — when the month averaged 15.8°C — while the coldest was 1995 at 9.2°C. Typical May days reach 21.1°C with nights near 5.6°C. The long-term May temperature trend is broadly flat.
May is a relatively wet time of year in Greeley, averaging 68 mm of rainfall. The wettest May on record was 1995 with 160 mm, while the driest was 2024 at 23 mm.
Relative humidity in Greeley during May averages 51%. The most humid May was 2015 at 69%, and the least humid was 2012 at 40%.
May receives about 6.3 kWh/m²/day of solar energy in Greeley. The sunniest Mays were 1998, 2000 and 2020 at 7 kWh/m²/day, and the cloudiest were 1995 and 2015 at 5.
Average wind speed in Greeley during May is 2.5 m/s. The windiest May was 1988 at 3.3 m/s, while the calmest were 2003 and 2007 at 2.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 13.1°C | 13.3°C | 14.3°C | 12.3°C | 13.9°C | +0.8°C |
| Avg High | 20.8°C | 21.1°C | 22.4°C | 19.8°C | 21.6°C | +0.8°C |
| Avg Low | 5.5°C | 5.5°C | 6.3°C | 4.8°C | 6.1°C | +0.6°C |
| Avg Rain | 71 mm | 67 mm | 54 mm | 83 mm | 66 mm | -5 mm |
May temperatures in Greeley have risen by about 1.2°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -9.9°C (2013) to a record high of 34.7°C (2003).
Rainfall in May is a relatively wet time of year, averaging 68 mm, with a wettest year of 160 mm.
A good time to visit Greeley
May is a good time to visit Greeley, with days averaging 21.1°C and nights around 5.6°C (mean 13.4°C, warmer than Greeley'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 | 21.9°C | 14.4°C | 6.8°C | 29.6°C | 1.2°C | 80 mm | 50% | 2.6 m/s | 6.4 |
| 2024 | 21.5°C | 13.4°C | 5.4°C | 30.3°C | -1.3°C | 23 mm | 45% | 2.8 m/s | 6.8 |
| 2023 | 22.3°C | 15.1°C | 7.9°C | 28.6°C | 2.8°C | 96 mm | 55% | 2.2 m/s | 6.2 |
| 2022 | 21.6°C | 13.4°C | 5.2°C | 32.7°C | -1.4°C | 69 mm | 45% | 2.7 m/s | 6.3 |
| 2021 | 19.7°C | 12.5°C | 5.3°C | 28.9°C | -2.5°C | 85 mm | 57% | 2.2 m/s | 5.8 |
| 2020 | 22.9°C | 14.4°C | 5.9°C | 31.6°C | -1.8°C | 45 mm | 48% | 2.5 m/s | 7 |
| 2019 | 17.5°C | 10.2°C | 2.9°C | 28.1°C | -3.2°C | 82 mm | 57% | 2.5 m/s | 5.9 |
| 2018 | 23.3°C | 15.6°C | 7.9°C | 32.2°C | 0.7°C | 76 mm | 51% | 2.2 m/s | 6.2 |
| 2017 | 20.0°C | 12.5°C | 4.9°C | 29.6°C | -4.6°C | 105 mm | 55% | 2.5 m/s | 6.3 |
| 2016 | 19.5°C | 12.0°C | 4.4°C | 27.8°C | -4.1°C | 66 mm | 55% | 2.2 m/s | 6.2 |
| 2015 | 16.5°C | 10.4°C | 4.2°C | 25.6°C | -4.2°C | 143 mm | 69% | 2.2 m/s | 5 |
| 2014 | 20.0°C | 12.8°C | 5.6°C | 29.7°C | -5.6°C | 97 mm | 57% | 2.6 m/s | 6.2 |
| 2013 | 20.7°C | 13.1°C | 5.5°C | 30.0°C | -9.9°C | 56 mm | 48% | 2.5 m/s | 6.7 |
| 2012 | 23.5°C | 15.2°C | 6.8°C | 33.0°C | 1.5°C | 34 mm | 40% | 2.3 m/s | 6.7 |
| 2011 | 17.9°C | 10.5°C | 3.1°C | 27.3°C | -2.8°C | 92 mm | 56% | 2.5 m/s | 5.4 |
| 2010 | 19.1°C | 11.0°C | 2.8°C | 31.9°C | -4.5°C | 76 mm | 55% | 2.7 m/s | 6.9 |
| 2009 | 21.7°C | 14.4°C | 7.1°C | 32.0°C | 1.5°C | 57 mm | 53% | 2.3 m/s | 6.3 |
| 2008 | 20.7°C | 12.7°C | 4.8°C | 30.4°C | -4.1°C | 62 mm | 48% | 2.9 m/s | 6.4 |
| 2007 | 22.1°C | 14.3°C | 6.5°C | 30.3°C | 0.6°C | 53 mm | 49% | 2.1 m/s | 6.6 |
| 2006 | 24.1°C | 15.7°C | 7.2°C | 32.6°C | -1.9°C | 32 mm | 40% | 2.6 m/s | 6.9 |
| 2005 | 21.7°C | 13.6°C | 5.5°C | 32.4°C | -6.0°C | 42 mm | 48% | 2.3 m/s | 6.6 |
| 2004 | 23.8°C | 15.2°C | 6.7°C | 30.7°C | -1.9°C | 47 mm | 41% | 2.7 m/s | 6.7 |
| 2003 | 21.7°C | 13.9°C | 6.1°C | 34.7°C | -3.1°C | 59 mm | 52% | 2.1 m/s | 6.5 |
| 2002 | 22.0°C | 13.4°C | 4.9°C | 33.9°C | -3.2°C | 46 mm | 40% | 2.3 m/s | 6.6 |
| 2001 | 21.6°C | 14.1°C | 6.7°C | 29.8°C | -2.0°C | 81 mm | 50% | 2.8 m/s | 6 |
| 2000 | 24.2°C | 15.7°C | 7.3°C | 34.2°C | -2.2°C | 56 mm | 42% | 2.6 m/s | 7 |
| 1999 | 19.2°C | 11.7°C | 4.1°C | 26.8°C | -3.4°C | 58 mm | 58% | 2.4 m/s | 6.5 |
| 1998 | 22.2°C | 14.1°C | 6.0°C | 30.0°C | -0.7°C | 52 mm | 49% | 2.2 m/s | 7 |
| 1997 | 21.2°C | 13.4°C | 5.5°C | 29.6°C | -3.0°C | 57 mm | 50% | 2.5 m/s | 6.8 |
| 1996 | 22.2°C | 14.0°C | 5.8°C | 31.9°C | -0.3°C | 80 mm | 52% | 2.2 m/s | 5.8 |
| 1995 ❄️ 🌧️ | 15.7°C | 9.2°C | 2.7°C | 26.3°C | -4.4°C | 160 mm | 66% | 2.6 m/s | 5 |
| 1994 🔥 | 23.8°C | 15.8°C | 7.7°C | 32.4°C | 2.0°C | 36 mm | 47% | 2.4 m/s | 6.6 |
| 1993 | 21.0°C | 13.5°C | 6.0°C | 27.3°C | -2.3°C | 42 mm | 54% | 2.2 m/s | 6.2 |
| 1992 | 22.7°C | 15.0°C | 7.3°C | 30.2°C | 2.4°C | 46 mm | 48% | 2.4 m/s | 6 |
| 1991 | 22.1°C | 14.1°C | 6.1°C | 29.5°C | -4.1°C | 77 mm | 51% | 2.6 m/s | 6.1 |
| 1990 | 20.6°C | 12.2°C | 3.9°C | 29.2°C | -3.1°C | 65 mm | 50% | 2.4 m/s | 6 |
| 1989 | 22.8°C | 14.3°C | 5.9°C | 31.5°C | -4.9°C | 49 mm | 43% | 2.6 m/s | 6.4 |
| 1988 | 21.9°C | 13.8°C | 5.8°C | 30.6°C | -2.9°C | 72 mm | 45% | 3.3 m/s | 6.1 |
| 1987 | 21.2°C | 14.4°C | 7.5°C | 27.8°C | 1.3°C | 89 mm | 55% | 2.4 m/s | 5.7 |
| 1986 | 20.6°C | 12.7°C | 4.9°C | 28.9°C | -1.3°C | 46 mm | 47% | 2.3 m/s | 6.5 |
| 1985 | 22.3°C | 14.6°C | 6.9°C | 29.2°C | 1.1°C | 35 mm | 44% | 2.5 m/s | 6.6 |
| 1984 | 23.2°C | 14.4°C | 5.6°C | 31.6°C | -2.9°C | 29 mm | 47% | 2.5 m/s | 6.5 |
| 1983 | 16.8°C | 10.0°C | 3.1°C | 27.0°C | -1.7°C | 97 mm | 58% | 2.6 m/s | — |
| 1982 | 18.9°C | 11.7°C | 4.5°C | 28.5°C | -2.5°C | 103 mm | 55% | 2.3 m/s | — |
| 1981 | 19.2°C | 12.1°C | 5.0°C | 26.4°C | -0.7°C | 117 mm | 56% | 2.5 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 21.1°C with lows near 5.6°C (mean 13.4°C), based on 45 years of NASA POWER data.
May averages 68 mm of rainfall in Greeley, a relatively wet time of year. The wettest on record was 160 mm in 1995.
The hottest May reached 34.7°C in 2003. The coldest dipped to -9.9°C in 2013.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 1.2°C. Daytime highs moved from 20.1°C to 21.4°C and overnight lows from 5°C to 6.1°C over the same span.
May is one of the warmer months of the year in Greeley and a relatively wet time of year, so plan for around 21.1°C daytime highs and 5.6°C at night.
Not quite — May is the 8th coolest month in Greeley, averaging 13.4°C.
For May in Greeley, pack warm layers and a jacket for chilly mornings, with typical highs of 21.1°C and lows of 5.6°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 51% — relatively dry.
Average wind speed in May is 2.5 m/s. The windiest May on record averaged 3.3 m/s (1988).
The wettest May on record was 1995 with 160 mm. On average, May sees 68 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 Greeley 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.
