September Weather in Santa Clara, United States

Last updated: June 24, 2025

In Santa Clara, United States, the average temperature in September hovers around 27°C (81°F), offering a delightful yet warm climate. Minimum temperatures can dip to 12°C (53°F), while maximums soar to a sizzling 39°C (102°F). Expect 111 mm (4.4 in) of precipitation spread over 11 days, contributing to an average humidity level of 65%. Embrace this dynamic weather as you explore the vibrant landscapes!

September Temperature in Santa Clara

In September in Santa Clara, the average temperature is 27°C (81°F), with maximums reaching 39°C (102°F) and minimums dropping to as low as 12°C (53°F). Travelers should be prepared for warm days and cooler nights, making it ideal to pack layers for comfort.

September Weather in Santa Clara: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Santa Clara, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Santa Clara, September typically has an average temperature of 27°C (81°F), with highs reaching up to 39°C (102°F) and lows dropping to around 12°C (53°F).

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

September Precipitation in Santa Clara

In Santa Clara in September, the precipitation amount is 111 mm (4.4 in), occurring over the course of 11 days.

September Precipitation Trends in Santa Clara

The chart displays monthly precipitation patterns in Santa Clara, 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 Santa Clara, September typically receives around 111 mm (4.4 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 Santa Clara

In Santa Clara in September, humidity is 65%. With an average temperature of 27°C (81°F), this humidity feels like a warm embrace, making travel feel both refreshing and slightly sticky as you explore the sights and sounds around you.

September Average Humidity in Santa Clara

This chart illustrates the average monthly humidity levels in Santa Clara, 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 Santa Clara is approximately 65%, 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 Santa Clara

In Santa Clara in September, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Santa Clara.

Maximum UV Index Levels in Santa Clara for September

The chart shows the monthly maximum UV Index (UVI) for Santa Clara 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 Santa Clara typically reaches 11, which falls under the extreme exposure category.

Data source: Santa Clara 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 Santa Clara Compares to Other Months

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

This table compares monthly weather conditions in Santa Clara, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	12°C (54°F)	43 mm (1.7 inches)	79%	moderate
February Weather	13°C (56°F)	51 mm (2.0 inches)	79%	very high
March Weather	19°C (66°F)	53 mm (2.1 inches)	74%	very high
April Weather	21°C (71°F)	84 mm (3.3 inches)	76%	extreme
May Weather	26°C (78°F)	116 mm (4.6 inches)	81%	extreme
June Weather	28°C (83°F)	84 mm (3.3 inches)	76%	extreme
July Weather	30°C (86°F)	70 mm (2.8 inches)	66%	extreme
August Weather	30°C (87°F)	82 mm (3.2 inches)	58%	extreme
September Weather	27°C (81°F)	111 mm (4.4 inches)	65%	extreme
October Weather	22°C (72°F)	78 mm (3.1 inches)	74%	very high
November Weather	17°C (62°F)	51 mm (2.0 inches)	81%	high
December Weather	14°C (57°F)	59 mm (2.3 inches)	86%	moderate