If you’re looking for Fall Fun, September in Boulder County is Awesome; here are some ideas:

September 1 and 23: Boulder Street Stampedes  Pearl Street Mall

September 10: Harvest Moon Triathlon, Boulder Rez

September 16,17,18: Boulder Fall Fest, Pearl Street Mall

September 18: Mapleton Hill Porchfest, Boulder

September 25: Longmont Oktoberfest, Longmont