Denver, Colorado Weather in September

September weather

Denver feels warm and sunny in September, with cooler evenings. The average high is 29°C and the low is 12°C. Rain is limited, but showers can still interrupt an outdoor plan.

It's a good month for walking around downtown, exploring the Denver Botanic Gardens or catching a Rockies game. Red Rocks is pleasant for a daytime visit, too. Save strenuous hikes for a cooler part of the day, and don't count on summer warmth after sunset. August is hotter and wetter; October brings cooler days.

Events and crowds

Denver Oktoberfest brings beer, food and music to Larimer Street in September. Labor Day weekend can also draw visitors, while the start of autumn brings a calmer feel than the busy summer months.

Families who want outdoor time without the hottest summer afternoons may find September a comfortable fit. Popular event areas can still feel crowded, especially during Oktoberfest, so quieter sightseeing is easier away from downtown festival streets.

Costs and local tips

September is a shoulder-season choice: summer's peak travel rush has eased, though big events can lift demand around their dates. Prices vary, but you'll often find the city less pressured than during peak summer weeks. Compared with October, September tends to be warmer and better for long days outside.

At Red Rocks, the steps and open amphitheatre sit high above Denver, so the sun can feel strong even when the air is cool. Check the venue's event schedule before setting out; a concert can change access and parking. After a show, give yourself time to get back down the winding road.