September Weather in Hamilton, United States

Last updated: June 24, 2025

In September, the average temperature in Hamilton, United States hovers around 21°C (70°F). However, be prepared for a range of extremes, with minimums dipping to 6°C (44°F) and maximums soaring to 35°C (95°F). Expect about 98 mm (3.9 in) of precipitation spread over 8 days, contributing to a relatively high average humidity of 78%.

September Temperature in Hamilton

In September in Hamilton, the average temperature is 21°C (70°F). Maximums can reach 35°C (95°F), while minimums can drop as low as 6°C (44°F). This varied climate makes Hamilton an ideal destination for travelers looking to experience both warm and cool weather during their visit.

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 21°C (70°F), with highs reaching up to 35°C (95°F) and lows dropping to around 6°C (44°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 total precipitation amount is 98 mm (3.9 in), occurring over 8 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 98 mm (3.9 inches) of precipitation spread over approximately 8 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 78%. With an average temperature of 21°C (70°F), this humidity feels like a warm, enveloping blanket that can leave travelers feeling sticky and slightly fatigued, making it important to stay hydrated and take frequent breaks from outdoor activities.

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 78%, 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 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 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 8, 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	-3°C (27°F)	57 mm (2.2 inches)	81%	moderate
February Weather	-2°C (29°F)	60 mm (2.4 inches)	81%	moderate
March Weather	6°C (43°F)	101 mm (4.0 inches)	81%	high
April Weather	11°C (52°F)	97 mm (3.8 inches)	82%	very high
May Weather	18°C (65°F)	166 mm (6.6 inches)	78%	very high
June Weather	24°C (76°F)	121 mm (4.8 inches)	81%	extreme
July Weather	26°C (79°F)	83 mm (3.3 inches)	79%	very high
August Weather	24°C (75°F)	84 mm (3.3 inches)	77%	very high
September Weather	21°C (70°F)	98 mm (3.9 inches)	78%	very high
October Weather	13°C (56°F)	112 mm (4.4 inches)	78%	high
November Weather	5°C (41°F)	52 mm (2.0 inches)	87%	moderate
December Weather	1°C (35°F)	43 mm (1.7 inches)	84%	low