Boulder weather by month
The best time to visit Boulder, United States is September. Pick a month for full climate normals and a verdict.
- Januarycold, dry, clean air53tier D
- Februarycold, a little rain, clean air56tier D
- Marchcold, a little rain, clean air69tier C
- Aprilcool, a little rain, reliable snow78tier B
- Maynice, rainy, clean air81tier A
- Junewarm, rainy, clean air90tier S
- Julyhot, a little rain87tier A
- Augusthot, a little rain, clean air91tier S
- Septemberwarm, a little rain, clean air93tier S
- Octobernice, dry, clean air83tier A
- Novembercool, dry, clean air71tier B
- Decembercold, dry, clean air60tier C