September Weather in Irvine, United States

Last updated: June 24, 2025

In September, the average temperature in Irvine, United States hovers around 22°C (71°F), with a minimum dipping to 7°C (46°F) and a maximum soaring to 36°C (97°F). Expect 111 mm (4.4 in) of precipitation spread over 9 days, and enjoy a comfortable average humidity level of 67%.

September Temperature in Irvine

In September in Irvine, the average temperature is 22°C (71°F). Maximums can reach 36°C (97°F), and minimums can drop to as low as 7°C (46°F). This makes it a perfect time for travelers to enjoy a pleasant climate while exploring the area.

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

The chart illustrates September temperature patterns in Irvine, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Irvine, September typically has an average temperature of 22°C (71°F), with highs reaching up to 36°C (97°F) and lows dropping to around 7°C (46°F).

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

September Precipitation in Irvine

In Irvine in September, the precipitation amount is 111 mm (4.4 in) over the course of 9 days.

September Precipitation Trends in Irvine

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

In Irvine in September, humidity is 67%. With an average temperature of 22°C (71°F), this humidity feels like a warm embrace, making outdoor activities enjoyable yet slightly uncomfortable, as the air hangs thick, reminding travelers to stay hydrated and seek shade during the midday sun.

September Average Humidity in Irvine

This chart illustrates the average monthly humidity levels in Irvine, 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 Irvine is approximately 67%, 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 Irvine

In Irvine 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 Irvine.

Maximum UV Index Levels in Irvine for September

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

Data source: Irvine 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 Irvine Compares to Other Months

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

This table compares monthly weather conditions in Irvine, 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 (37°F)	94 mm (3.7 inches)	88%	moderate
February Weather	5°C (42°F)	153 mm (6.0 inches)	88%	high
March Weather	9°C (49°F)	125 mm (4.9 inches)	87%	high
April Weather	13°C (57°F)	134 mm (5.3 inches)	84%	very high
May Weather	19°C (67°F)	123 mm (4.9 inches)	84%	very high
June Weather	23°C (73°F)	171 mm (6.7 inches)	83%	extreme
July Weather	25°C (78°F)	100 mm (4.0 inches)	79%	extreme
August Weather	24°C (76°F)	115 mm (4.5 inches)	66%	very high
September Weather	22°C (71°F)	111 mm (4.4 inches)	67%	very high
October Weather	16°C (61°F)	113 mm (4.4 inches)	76%	high
November Weather	8°C (46°F)	80 mm (3.2 inches)	89%	moderate
December Weather	5°C (42°F)	127 mm (5.0 inches)	88%	moderate