Boulder weather in May
May in Boulder: nice, rainy, with clean air — an excellent time to visit.
#6 of 12 months in Boulder · #485 of 897 destinations to visit in May · comfort 81/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Traveller notes on Boulder in May
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Boulder climate normals — May
| Daytime high | 20°C / 67°F | 😎 nice |
|---|---|---|
| Nighttime low | 5°C / 40°F | |
| Rainfall | 121 mm / 4.8 in | 🌧 rainy |
| Rainy days | 18 days | |
| Humidity | 62% | 💧 humid |
| Dew point | 4°C / 39°F | |
| Sunshine | 11.9 h/day | |
| Daylight | 14.4 h | |
| Wind | 14 km/h / 9 mph | |
| Snowfall | 16.1 cm / 6.3 in | |
| Air quality (US AQI) | 50 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Boulder in May — FAQ
- Is May a good time to visit Boulder?
- May in Boulder: nice, rainy, with clean air — an excellent time to visit. It ranks #6 of 12 months for Boulder on SeasonMap's comfort score (81/100).
- What is the weather like in Boulder in May?
- In May, Boulder averages a daily high of 19.6°C and a low of 4.7°C, with about 121.2 mm of rain over roughly 17.6 rainy days.
- What is the air quality in Boulder in May?
- Boulder has a mean US Air Quality Index of about 50 in May.
- Does it snow in Boulder in May?
- Boulder sees roughly 16.1 cm of snowfall in May.