September Weather in South Pasadena, United States

Last updated: June 24, 2025

In South Pasadena, United States, the average temperature in September hovers around 23°C (74°F). However, be prepared for a minimum of 13°C (55°F) and the occasional spike up to 45°C (113°F). With only 3 mm (0.1 in) of precipitation expected over 0 days, you can enjoy a relatively dry atmosphere complemented by an average humidity of 68%.

September Temperature in South Pasadena

In September, South Pasadena experiences an average temperature of 23°C (74°F). The maximum can reach 45°C (113°F), while the minimum can drop to as low as 13°C (55°F). Travelers should be prepared for warm days and cool evenings while exploring the diverse climate of South Pasadena.

September Weather in South Pasadena: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in South Pasadena, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In South Pasadena, September typically has an average temperature of 23°C (74°F), with highs reaching up to 45°C (113°F) and lows dropping to around 13°C (55°F).

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

September Precipitation in South Pasadena

In South Pasadena in September, the precipitation amount is 3 mm (0.1 in) during a total of 0 days.

September Precipitation Trends in South Pasadena

The chart displays monthly precipitation patterns in South Pasadena, 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 South Pasadena, September typically receives around 3 mm (0.1 inches) of precipitation spread over approximately 0 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 South Pasadena

In South Pasadena in September, humidity is 68%. With an average temperature of 23°C (74°F), this humidity feels like a warm embrace, making traveling quite uncomfortable if you're not prepared. The air is thick and muggy, leaving you yearning for a cool breeze and frequent breaks in the shade.

September Average Humidity in South Pasadena

This chart illustrates the average monthly humidity levels in South Pasadena, 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 South Pasadena 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 South Pasadena

In South Pasadena in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in South Pasadena.

Maximum UV Index Levels in South Pasadena for September

The chart shows the monthly maximum UV Index (UVI) for South Pasadena 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 South Pasadena typically reaches 10, which falls under the very high exposure category.

Data source: South Pasadena 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 South Pasadena Compares to Other Months

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

This table compares monthly weather conditions in South Pasadena, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	13°C (57°F)	71 mm (2.8 inches)	74%	moderate
February Weather	14°C (57°F)	55 mm (2.2 inches)	79%	high
March Weather	15°C (59°F)	70 mm (2.8 inches)	75%	very high
April Weather	18°C (64°F)	19 mm (0.7 inches)	70%	very high
May Weather	19°C (66°F)	12 mm (0.5 inches)	70%	very high
June Weather	21°C (70°F)	3 mm (0.1 inches)	72%	extreme
July Weather	24°C (75°F)	2 mm (0.1 inches)	73%	extreme
August Weather	24°C (76°F)	2 mm (0.1 inches)	69%	very high
September Weather	23°C (74°F)	3 mm (0.1 inches)	68%	very high
October Weather	21°C (70°F)	8 mm (0.3 inches)	67%	high
November Weather	17°C (63°F)	17 mm (0.7 inches)	68%	moderate
December Weather	13°C (57°F)	76 mm (3.0 inches)	71%	moderate