Weather in Longmont in September
Longmont, United States averages a high of 24.7°C (76.5°F) and low of 10.1°C (50.2°F) in September, with 5 rain days and 10.9 hours of daily sunshine. Travel score: 89.7/100 (Excellent). The best time to visit Longmont is August.
High
25°C76°F
Low
10°C50°F
🌧️
5
rain days
☀️
10.9
hrs/day sunshine
💧
55%
humidity
90— Excellent
September in Longmont is warm and mostly dry — ideal for sightseeing and outdoor activities.
What are the average temperatures in Longmont?
How much does it rain in Longmont in September?
Longmont receives an average of 36.8mm of rainfall across 5 rainy days in September. The annual total is 472.8mm.
What should I pack for Longmont in September?
Essentials
👟
Comfortable walking shoes
Essential for exploring the city
👕
Light layers and t-shirts
Warm weather around 25°C
🧴
Sunscreen SPF 30+
11 hours of sunshine daily
🕶️
Sunglasses
Protect your eyes from bright sun
Recommended
🧥
Evening jacket or cardigan
Temperature drops 15°C from day to night
Traveling to United States in September?
Don't let a public holiday surprise you — restaurants, shops, and attractions may be closed.
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Data based on 1994–2024 averages · Last updated: 2024-12-31