Boulder, CO Weather
Boulder hourly forecast: next 24 hours
Today's high of 91°F (33°C) is about 6°F (3°C) above the typical July high of 85°F (30°C).
Current conditions in detail
Boulder weather tomorrow (Saturday, July 18)
Tomorrow in Boulder looks sunny, with a high of 94° and an overnight low of 60°. Rain is unlikely (1% chance). Winds top out near 11 mph, and the UV index reaches 12 (extreme).
Boulder 14-day forecast
About the weather in Boulder
Located in Colorado, United States, Boulder experiences a humid subtropical climate with hot, humid summers and generally mild winters. Afternoon temperatures peak near 85°F (30°C) in July and dip to about 38°F (3°C) in January, with around 20.6 inches (524 mm) of precipitation falling across the year.
Boulder weather: quick facts
- Hottest month: July - highs near 85°F (30°C)
- Coldest month: January - highs near 38°F (3°C)
- Record high: 98°F (37°C) · Record low: -24°F (-31°C) (2015–2024)
- Wettest month: May (15 rainy days) · Sunniest: July (13.1 h sun/day)
- Climate type: humid subtropical - hot, humid summers and generally mild winters
- Snow: about 34 days a year
Temperatures through the year
The warmest stretch of the year centers on July. Highs average 85°F (30°C) and overnight lows stay near 59°F (15°C). The coolest month is January, with typical highs of 38°F (3°C) and lows around 17°F (-8°C). Based on 2015–2024 weather data, temperatures have reached as high as 98°F (37°C) and dropped as low as -24°F (-31°C).
Rain, sun and snow
May is usually the wettest month. It brings about 4.6 inches (116 mm) of rain over 15 days, while December is the driest. July brings the most sunshine, averaging 13.1 hours of sun a day. Snow falls on about 34 days in a typical year, mostly from October through May.
Season by season
Spring (March through May)
Spring in Boulder is mild, with daytime highs averaging 57°F (14°C) and nights around 32°F (0°C); expect showers on roughly 33 days across the season, plus around 13 snowy days.
Summer (June through August)
Summer in Boulder is hot, with daytime highs averaging 83°F (28°C) and nights around 57°F (14°C); expect showers on roughly 25 days across the season.
Fall (September through November)
Fall in Boulder stays on the cool side of mild, with daytime highs averaging 64°F (18°C) and nights around 39°F (4°C); expect showers on roughly 18 days across the season, plus around 7 snowy days.
Winter (December through February)
Winter in Boulder runs cold, with daytime highs averaging 40°F (4°C) and nights around 18°F (-8°C); expect showers on roughly 18 days across the season, plus around 14 snowy days.
Average temperatures in Boulder by month
| Month | High | Low | Rain days | Precipitation | Sunshine | Humidity |
|---|---|---|---|---|---|---|
| January | 38° | 17° | 6 | 1.0 in | 7.9 h/day | 61% |
| February | 39° | 15° | 7 | 1.4 in | 9.1 h/day | 61% |
| March | 49° | 24° | 8 | 2.1 in | 10.1 h/day | 61% |
| April | 57° | 31° | 10 | 2.3 in | 10.9 h/day | 58% |
| May | 65° | 41° | 15 | 4.6 in | 11.7 h/day | 64% |
| June | 80° | 54° | 8 | 1.9 in | 13.0 h/day | 52% |
| July | 85° | 59° | 9 | 1.5 in | 13.1 h/day | 50% |
| August | 83° | 58° | 8 | 1.4 in | 12.3 h/day | 50% |
| September | 78° | 52° | 6 | 1.0 in | 11.2 h/day | 47% |
| October | 63° | 38° | 6 | 1.3 in | 9.7 h/day | 53% |
| November | 49° | 27° | 6 | 1.3 in | 8.5 h/day | 57% |
| December | 42° | 20° | 5 | 0.9 in | 7.8 h/day | 56% |