Grand Junction (CO)
September
Weather in Grand Junction, Colorado for September 2026
Your guide to Grand Junction weather in September - trends and predictions
So far, September 2026 in Grand Junction is slightly warmer than the historical average by 0.7 °F.
The forecast for the upcoming days in Grand Junction predicts a temperature of 23.5 °F, which is slightly above the historical average.
In general, the average temperature in Grand Junction at the beginning of September is 31.7 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 22.4 °F by the end of September.
With an average of 4 rainy days, Grand Junction experiences minimal rainfall in September.
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Temperatures
Rain 🌧️
More
26
Dry days
4
Rainy days
0
Snow days
27°/9°
Temperatures
19 km/h
Avg max wind
44 %
Avg humidity
Grand Junction Weather September
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Temperatures trend during September in Grand Junction
See the weather trend as well as the moving average line
September weather in Grand Junction day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 31° /11° | 2.1 mm | 8 | |
| Sept. 2 | Sunny | 31° /13° | 18.5 mm | 8 | |
| Sept. 3 |  Partly cloudy | 34° /13° | 0 mm | 9 | |
| Sept. 4 | Sunny | 34° /14° | 0 mm | 9 | |
| Sept. 5 | Sunny | 32° /15° | 0 mm | 9 | |
| Sept. 6 | Partly cloudy | 30° /13° | 0.1 mm | 6 | |
| Sept. 7 | Sunny | 30° /13° | 0 mm | 6 | |
| Sept. 8 | Sunny | 32° /12° | 0 mm | 8 | |
| Sept. 9 |  Cloudy | 31° /12° | 0 mm | 8 | |
| Sept. 10 | Sunny | 32° /12° | 0 mm | 9 | |
| Sept. 11 |  Thundery outbreaks possible | 30° /13° | 3 mm | 7 | |
| Sept. 12 |  Moderate or heavy rain shower | 28° /13° | 16 mm | 5 | |
| Sept. 13 |  Torrential rain shower | 26° /12° | 26.8 mm | 6 | |
| Sept. 14 | Sunny | 25° /11° | 1 mm | 5 | |
| Sept. 15 | Partly cloudy | 29° /10° | 3.9 mm | 7 | |
| Sept. 16 | Sunny | 28° /10° | 1 mm | 4 | |
| Sept. 17 | Sunny | 22° /13° | 5.2 mm | 4 | |
| Sept. 18 | Sunny | 26° /10° | 2.2 mm | 6 | |
| Sept. 19 |  Overcast | 25° /10° | 6.8 mm | 6 | |
| Sept. 20 | Partly cloudy | 25° /10° | 0 mm | 7 | |
| Sept. 21 | Partly cloudy | 25° /9° | 0 mm | 6 | |
| Sept. 22 |  Patchy rain possible | 27° /11° | 1.9 mm | 6 | |
| Sept. 23 | Sunny | 22° /10° | 1.6 mm | 4 | |
| Sept. 24 | Sunny | 24° /8° | 0.2 mm | 4 | |
| Sept. 25 | Sunny | 25° /9° | 1.2 mm | 5 | |
| Sept. 26 | Sunny | 24° /14° | 0 mm | 5.5 | |
| Sept. 27 | Overcast | 26° /15° | 0 mm | 5.6 | |
| Sept. 28 | Overcast | 18° /12° | 4.1 mm | 2 | |
| Sept. 29 | Light rain shower | 16° /12° | 10.7 mm | 2.4 | |
| Sept. 30 | Sunny | 24° /13° | 0 mm | 6.4 | |
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Important Notice
Our weather forecast for Grand Junction in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Grand Junction forecast closer to your planned date for the most up-to-date weather information.
Change Month
Grand Junction in September - FAQ
What are the expected maximum and minimum temperatures in Grand Junction during September?
Enjoy moderate daytime temperatures of up to 27° and cooler nights around 9°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Grand Junction during September?
Moderate rainfall is anticipated in Grand Junction during September, with a total of 94.9 mm spread over approximately 4 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Grand Junction during September?
The average wind speed in Grand Junction during September is 19 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Grand Junction
Explore the daily rainfall trends and prepare for Grand Junctions September weather 💧
Typically, Grand Junction has 4 rainy days in September with a total of 94.9 mm of rainfall.
UV exposure in Grand Junction during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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