September Weather in Hamilton, United States

Last updated: June 24, 2025

In September, the average temperature in Hamilton, United States hovers around 25°C (77°F), providing a pleasant climate for outdoor activities. However, be prepared for a range, as temperatures can dip to a cool 12°C (54°F) and soar as high as 37°C (98°F). Expect some rain, with 100 mm (3.9 in) of precipitation spread over 9 days. Plus, a relatively high average humidity of 82% adds a touch of tropical feel to your experience.

September Temperature in Hamilton

In September in Hamilton, the average temperature is 25°C (77°F). Maximums can reach 37°C (98°F) and minimums can be as low as 12°C (54°F). It's an ideal time for travelers seeking warm weather while also enjoying some cooler evenings.

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

The chart illustrates September temperature patterns in Hamilton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Hamilton, September typically has an average temperature of 25°C (77°F), with highs reaching up to 37°C (98°F) and lows dropping to around 12°C (54°F).

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

September Precipitation in Hamilton

In Hamilton in September, the precipitation amount is 100 mm (3.9 in) spread over 9 days.

September Precipitation Trends in Hamilton

The chart displays monthly precipitation patterns in Hamilton, 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 Hamilton, September typically receives around 100 mm (3.9 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 Hamilton

In Hamilton in September, humidity is 82%. With an average temperature of 25°C (77°F), this humidity feels like a warm, oppressive blanket enveloping you as you explore, making every step feel more laborious and prompting the need for frequent hydration breaks.

September Average Humidity in Hamilton

This chart illustrates the average monthly humidity levels in Hamilton, 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 Hamilton is approximately 82%, 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 Hamilton

In Hamilton in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Hamilton.

Maximum UV Index Levels in Hamilton for September

The chart shows the monthly maximum UV Index (UVI) for Hamilton 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 Hamilton typically reaches 9, which falls under the very high exposure category.

Data source: Hamilton 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 Hamilton Compares to Other Months

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

This table compares monthly weather conditions in Hamilton, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	9°C (49°F)	114 mm (4.5 inches)	86%	moderate
February Weather	12°C (55°F)	118 mm (4.6 inches)	84%	high
March Weather	15°C (59°F)	92 mm (3.6 inches)	83%	very high
April Weather	18°C (65°F)	106 mm (4.2 inches)	81%	very high
May Weather	22°C (73°F)	105 mm (4.1 inches)	81%	extreme
June Weather	25°C (78°F)	121 mm (4.8 inches)	81%	extreme
July Weather	27°C (80°F)	112 mm (4.4 inches)	83%	extreme
August Weather	26°C (80°F)	126 mm (5.0 inches)	81%	extreme
September Weather	25°C (77°F)	100 mm (3.9 inches)	82%	very high
October Weather	20°C (69°F)	110 mm (4.3 inches)	78%	very high
November Weather	13°C (55°F)	76 mm (3.0 inches)	86%	high
December Weather	10°C (51°F)	132 mm (5.2 inches)	89%	moderate