Weather in Tri-Cities in September
Tri-Cities, United States averages a high of 27.6°C (81.7°F) and low of 13.9°C (57°F) in September, with 2 rain days and 11.2 hours of daily sunshine. Travel score: 97.6/100 (Excellent). The best time to visit Tri-Cities is August.
High
28°C82°F
Low
14°C57°F
🌧️
2
rain days
☀️
11.2
hrs/day sunshine
💧
46%
humidity
98— Excellent
September in Tri-Cities is warm and dry — ideal for sightseeing and outdoor activities.
What are the average temperatures in Tri-Cities?
How much does it rain in Tri-Cities in September?
Tri-Cities receives an average of 7.6mm of rainfall across 2 rainy days in September. The annual total is 229.1mm.
What should I pack for Tri-Cities in September?
Essentials
👟
Comfortable walking shoes
Essential for exploring the city
👕
Light layers and t-shirts
Warm weather around 28°C
🧴
Sunscreen SPF 30+
11 hours of sunshine daily
🕶️
Sunglasses
Protect your eyes from bright sun
Recommended
🧥
Evening jacket or cardigan
Temperature drops 14°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