Weather in Denver in September 2025
Average weather
Average temperature in Denver in September
Going from a maximum of +36°C during the day to a minimum of +6°C during the night, the temperature in September averages around +28°C.
The average maximum temperature goes down 17% by the end of the month, compared with the beginning of the month, from +36°C to +31°C.
Is Denver warm or cold in September?
Denver is typically warm in September.
Maximum temperatures go down compared to the previous month from +30°C to +26°C. The minimum temperature also goes down from +15°C to +11°C.
It’s generally warm, but pack a long-sleeve shirt for evenings.
Take a look at how September is compared to other months in Denver:
Climate in Denver in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +30°C | +26°C | +19°C | ||||
| Min. temperature | ||||||
| +5°C | -10°C | -21°C | ||||
| Max. temperature | ||||||
| +38°C | +37°C | +31°C | ||||
| Rainfall | ||||||
| 50 mm | 41 mm | 28 mm | ||||
| Wind | ||||||
| 1 m/s | 1 m/s | 1 m/s | ||||
| Humidity | ||||||
| 53% | 52% | 54% | ||||
| Air pressure | ||||||
| 1015 HPa | 1015 HPa | 1015 HPa | ||||
| Sunny days | ||||||
| 7 | 12 | 12 | ||||
| Cloudy days | ||||||
| 6 | 6 | 9 | ||||
| Rainy days | ||||||
| 15 | 10 | 7 | ||||
| Snowy days | ||||||
| 0 | 0 | 2 | ||||
September weather is still as good as in August. It’s getting colder in September. From +30°C in the day, the average maximum temperature lowers to +26°C. As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 50 mm to 41 mm. It feels drier, as humidity decreases from 53% to 52%. The average wind speed doesn’t change much during September, staying around 1 m/s. The good news is there are likely to be more sunny days in September, from 7 to 12.
October brings much the same weather, it remains good.
Wind
The average wind speed is 1 m/s getting up to 2 m/s which is a light breeze; barely moving the tree leaves.
The average wind speed in Denver is gradually increasing during September, going from 1 m/s to 1 m/s over the course of the month.
Rain
Snow
Here’s how September is compared with other months in the amount of snow, total mm:
How was the weather last September in Denver?
Climate Change over Years
The climate in Denver in September has not changed much over the last 43 years.
The average temperature was the lowest in 1983 (+16°C) and the highest in 2012 (+20°C). The driest year was 2002 with only 211 mm of rainfall, and the wettest year was 2023 with 681 mm.
FAQ
Is September a good time to visit Denver?
Can you sunbathe in Denver in September?
Is Denver rainy in September?
Is it sunny in Denver in September?
Other cities in USA
Monthly weather in Denver
Source of the data
For this page, we’ve looked at the typical weather in Denver, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.