September Weather in Allendale, United States

Last updated: June 24, 2025

In Allendale, United States, the average temperature in September hovers around 20°C (68°F), with temperatures ranging from a chilly 5°C (42°F) to a warm 34°C (93°F). During this month, expect about 114 mm (4.5 in) of precipitation spread across 11 days, and enjoy a comfortable average humidity level of 68%.

September Temperature in Allendale

In September in Allendale, the average temperature is 20°C (68°F). Maximum can reach 34°C (93°F) and minimum can be as low as 5°C (42°F). Pack accordingly to enjoy a comfortable and pleasant trip!

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

The chart illustrates September temperature patterns in Allendale, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Allendale, September typically has an average temperature of 20°C (68°F), with highs reaching up to 34°C (93°F) and lows dropping to around 5°C (42°F).

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

September Precipitation in Allendale

In Allendale in September, the total precipitation amount is 114 mm (4.5 in) spread over 11 days.

September Precipitation Trends in Allendale

The chart displays monthly precipitation patterns in Allendale, 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 Allendale, September typically receives around 114 mm (4.5 inches) of precipitation spread over approximately 11 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 Allendale

In Allendale in September humidity is 68%. With an average temperature of 20°C (68°F), this humidity feels like a warm embrace, making it ideal for leisurely strolls while also prompting travelers to stay hydrated and seek out refreshing breaks from the heat.

September Average Humidity in Allendale

This chart illustrates the average monthly humidity levels in Allendale, 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 Allendale is approximately 68%, 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 Allendale

In Allendale 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 Allendale.

Maximum UV Index Levels in Allendale for September

The chart shows the monthly maximum UV Index (UVI) for Allendale 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 Allendale typically reaches 8, which falls under the very high exposure category.

Data source: Allendale 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 Allendale Compares to Other Months

Weather in Allendale varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Allendale, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Allendale, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	0°C (32°F)	70 mm (2.8 inches)	84%	moderate
February Weather	2°C (35°F)	99 mm (3.9 inches)	82%	moderate
March Weather	4°C (40°F)	95 mm (3.8 inches)	81%	high
April Weather	10°C (51°F)	118 mm (4.7 inches)	78%	very high
May Weather	16°C (61°F)	130 mm (5.1 inches)	69%	very high
June Weather	21°C (70°F)	99 mm (3.9 inches)	69%	very high
July Weather	24°C (76°F)	147 mm (5.8 inches)	62%	very high
August Weather	23°C (74°F)	131 mm (5.2 inches)	65%	very high
September Weather	20°C (68°F)	114 mm (4.5 inches)	68%	very high
October Weather	14°C (58°F)	141 mm (5.6 inches)	74%	high
November Weather	6°C (44°F)	88 mm (3.5 inches)	82%	moderate
December Weather	2°C (36°F)	111 mm (4.4 inches)	80%	low