September Weather in Livermore, United States

Last updated: June 24, 2025

In September, the average temperature in Livermore, United States is a pleasant 21°C (69°F), with a minimum dipping to 7°C (44°F) and a maximum soaring to 40°C (105°F). This month typically brings just 2 mm (0.1 in) of precipitation over 0 days, while the average humidity hovers around a comfortable 55%. Enjoy the mild weather and clear skies!

September Temperature in Livermore

In September in Livermore, the average temperature is 21°C (69°F). The maximum can reach 40°C (105°F), while the minimum can drop to as low as 7°C (44°F). This diverse temperature range makes it essential for travelers to pack accordingly for both warm days and cooler evenings.

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

The chart illustrates September temperature patterns in Livermore, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Livermore, September typically has an average temperature of 21°C (69°F), with highs reaching up to 40°C (105°F) and lows dropping to around 7°C (44°F).

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

September Precipitation in Livermore

In Livermore in September, the precipitation amount is 2 mm (0.1 in) during a span of 0 days.

September Precipitation Trends in Livermore

The chart displays monthly precipitation patterns in Livermore, 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 Livermore, September typically receives around 2 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.

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Livermore

In Livermore in September, humidity is 55%. With an average temperature of 21°C (69°F), this humidity feels like a refreshing embrace, making it quite pleasant for traveling as long as you stay hydrated and take frequent breaks in the shade.

September Average Humidity in Livermore

This chart illustrates the average monthly humidity levels in Livermore, 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 Livermore is approximately 55%, 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 Livermore

In Livermore 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 Livermore.

Maximum UV Index Levels in Livermore for September

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

Data source: Livermore 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 Livermore Compares to Other Months

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

This table compares monthly weather conditions in Livermore, 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)	93 mm (3.7 inches)	82%	moderate
February Weather	11°C (51°F)	81 mm (3.2 inches)	84%	moderate
March Weather	12°C (54°F)	74 mm (2.9 inches)	82%	very high
April Weather	14°C (58°F)	28 mm (1.1 inches)	78%	very high
May Weather	17°C (63°F)	16 mm (0.6 inches)	71%	extreme
June Weather	20°C (69°F)	1 mm (0.0 inches)	64%	extreme
July Weather	22°C (72°F)	0 mm (0.0 inches)	58%	extreme
August Weather	22°C (72°F)	0 mm (0.0 inches)	54%	very high
September Weather	21°C (69°F)	2 mm (0.1 inches)	55%	very high
October Weather	17°C (63°F)	22 mm (0.9 inches)	62%	high
November Weather	13°C (55°F)	35 mm (1.4 inches)	78%	moderate
December Weather	9°C (49°F)	78 mm (3.1 inches)	80%	moderate