Last updated: June 24, 2025
In Grantsville, United States, the average temperature in September hovers around 18°C (64°F), with a range stretching from a cool 2°C (37°F) to a warm 30°C (86°F). Expect approximately 119 mm (4.7 in) of precipitation over 11 days, adding to an average humidity of 68%. Whether you're enjoying the mild weather or preparing for some rain, it's the perfect time to experience all that this vibrant locale has to offer!
In September in Grantsville, the average temperature is 18°C (64°F). The maximum can reach 30°C (86°F) and the minimum can be as low as 2°C (37°F). This varied climate makes Grantsville an ideal destination for travelers seeking both warm and cool experiences.
In Grantsville in September, the total precipitation amount is 119 mm (4.7 in), which occurs over the course of 11 days.
In Grantsville in September, humidity is 68%. With an average temperature of 18°C (64°F), this humidity feels like a warm embrace, making for a slightly muggy experience that can leave you feeling sticky as you explore, so it’s best to stay hydrated and take frequent breaks in the shade.
In Grantsville in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Grantsville.
UV Risk Categories
Weather in Grantsville varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Grantsville, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -2°C (29°F) | 88 mm (3.5 inches) | 86% | moderate |
| February Weather | 1°C (33°F) | 132 mm (5.2 inches) | 86% | moderate |
| March Weather | 4°C (39°F) | 115 mm (4.5 inches) | 86% | high |
| April Weather | 9°C (49°F) | 137 mm (5.4 inches) | 84% | very high |
| May Weather | 15°C (59°F) | 155 mm (6.1 inches) | 78% | very high |
| June Weather | 19°C (67°F) | 150 mm (5.9 inches) | 79% | very high |
| July Weather | 22°C (71°F) | 105 mm (4.1 inches) | 70% | very high |
| August Weather | 21°C (70°F) | 99 mm (3.9 inches) | 59% | very high |
| September Weather | 18°C (64°F) | 119 mm (4.7 inches) | 68% | very high |
| October Weather | 12°C (54°F) | 115 mm (4.5 inches) | 80% | high |
| November Weather | 4°C (40°F) | 85 mm (3.3 inches) | 86% | moderate |
| December Weather | 1°C (34°F) | 121 mm (4.8 inches) | 85% | moderate |