Verdict: Excellent month
Denver Weather in September
September runs warm in Denver, with daily highs around 28°C (82°F) and nights near 11°C (52°F). Rain is occasional — about 5 wet days in a typical year. Overall, September is one of the best months of the year to be in Denver.
Average high
28°C / 82°F
Average low
11°C / 52°F
Rain days
~5
Precipitation
23 mm
What to pack for Denver in September
- Summer clothes, plus one light layer for air-con and evenings
- High-SPF sunscreen, sunglasses, and a refillable water bottle
- Comfortable walking shoes — every guide on this site assumes you'll use them
September against the rest of the year
Warmest in Denver: Jul (32°C / 90°F) · Coolest: Jan (5°C / 41°F) · Wettest: May (~10 rain days)
5°
-9°
Jan
5°
-11°
Feb
10°
-5°
Mar
16°
0°
Apr
22°
6°
May
29°
13°
Jun
32°
16°
Jul
32°
16°
Aug
28°
11°
Sep
20°
4°
Oct
12°
-3°
Nov
8°
-5°
Dec
Daily highs / lows in °C · bars show rain days per month · ERA5 climate normals (2020–2024)