September Weather in Grantsville, United States

Last updated: June 24, 2025

In Grantsville, United States, the average temperature in September hovers around 21°C (70°F). However, visitors should be prepared for a range, as it can dip to a chilly 5°C (41°F) or soar to a sweltering 36°C (97°F). Expect about 106 mm (4.2 in) of precipitation over 9 days, contributing to an average humidity of 73%. Whether you're bracing for warmth or cool breezes, pack accordingly!

September Temperature in Grantsville

In September in Grantsville, the average temperature is 21°C (70°F). Maximums can reach 36°C (97°F), and minimums can dip as low as 5°C (41°F). It's a great time to visit for those who enjoy mild weather with the possibility of warm days and cool evenings.

September Weather in Grantsville: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Grantsville, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Grantsville, September typically has an average temperature of 21°C (70°F), with highs reaching up to 36°C (97°F) and lows dropping to around 5°C (41°F).

Data source: Temperature data for Grantsville generated using information from the Copernicus Climate Change Service.

September Precipitation in Grantsville

In Grantsville in September, the total precipitation amount is 106 mm (4.2 in), spread over the course of 9 days.

September Precipitation Trends in Grantsville

The chart displays monthly precipitation patterns in Grantsville, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Grantsville, September typically receives around 106 mm (4.2 inches) of precipitation spread over approximately 9 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

September Humidity in Grantsville

In Grantsville in September, humidity is 73%. With an average temperature of 21°C (70°F), this humidity feels like a warm embrace that can make outdoor activities feel sweltering, so it's essential to stay hydrated and take breaks in the shade while exploring.

September Average Humidity in Grantsville

This chart illustrates the average monthly humidity levels in Grantsville, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Grantsville is approximately 73%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Grantsville

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.

Maximum UV Index Levels in Grantsville for September

The chart shows the monthly maximum UV Index (UVI) for Grantsville in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Grantsville typically reaches 8, which falls under the very high exposure category.

Data source: Grantsville September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How September Weather in Grantsville Compares to Other Months

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.

This table compares monthly weather conditions in Grantsville, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	2°C (35°F)	98 mm (3.9 inches)	88%	moderate
February Weather	4°C (40°F)	142 mm (5.6 inches)	88%	moderate
March Weather	8°C (46°F)	115 mm (4.5 inches)	88%	high
April Weather	13°C (55°F)	142 mm (5.6 inches)	86%	very high
May Weather	18°C (65°F)	160 mm (6.3 inches)	82%	very high
June Weather	22°C (72°F)	172 mm (6.8 inches)	84%	very high
July Weather	24°C (76°F)	129 mm (5.1 inches)	82%	very high
August Weather	23°C (74°F)	120 mm (4.7 inches)	73%	very high
September Weather	21°C (70°F)	106 mm (4.2 inches)	73%	very high
October Weather	15°C (60°F)	116 mm (4.6 inches)	81%	high
November Weather	7°C (45°F)	81 mm (3.2 inches)	89%	moderate
December Weather	4°C (40°F)	122 mm (4.8 inches)	86%	moderate