September Weather in Atascadero, United States

Last updated: June 24, 2025

In Atascadero, United States, the average temperature in September hovers around 20°C (68°F). Expect a minimum of 9°C (49°F) and a maximum soaring up to 37°C (100°F). With just 1 mm (0.0 in) of precipitation over 0 days, you can anticipate a dry month, complemented by an average humidity of 70%. Enjoy the ideal climate!

September Temperature in Atascadero

In September in Atascadero, the average temperature is 20°C (68°F). Maximums can reach up to 37°C (100°F), and minimums can drop to as low as 9°C (49°F). It's advisable to pack for both warm and cooler weather when traveling during this month.

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

The chart illustrates September temperature patterns in Atascadero, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Atascadero, September typically has an average temperature of 20°C (68°F), with highs reaching up to 37°C (100°F) and lows dropping to around 9°C (49°F).

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

September Precipitation in Atascadero

In Atascadero in September, the precipitation amount is 1 mm (0.0 in) during a span of 0 days.

September Precipitation Trends in Atascadero

The chart displays monthly precipitation patterns in Atascadero, 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 Atascadero, September typically receives around 1 mm (0.0 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 Atascadero

In Atascadero in September, humidity is 70%. With an average temperature of 20°C (68°F), this humidity feels like a warm embrace that can make traveling a bit heavy and sticky but also invigorating, as the moisture in the air invigorates your skin and keeps you refreshed during your adventures.

September Average Humidity in Atascadero

This chart illustrates the average monthly humidity levels in Atascadero, 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 Atascadero is approximately 70%, 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 Atascadero

In Atascadero 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 Atascadero.

Maximum UV Index Levels in Atascadero for September

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

Data source: Atascadero 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 Atascadero Compares to Other Months

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

This table compares monthly weather conditions in Atascadero, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	11°C (51°F)	94 mm (3.7 inches)	80%	moderate
February Weather	11°C (52°F)	68 mm (2.7 inches)	83%	moderate
March Weather	12°C (54°F)	75 mm (3.0 inches)	80%	very high
April Weather	14°C (58°F)	20 mm (0.8 inches)	76%	very high
May Weather	16°C (61°F)	10 mm (0.4 inches)	75%	extreme
June Weather	19°C (66°F)	1 mm (0.0 inches)	74%	extreme
July Weather	20°C (68°F)	1 mm (0.0 inches)	75%	extreme
August Weather	20°C (69°F)	1 mm (0.0 inches)	72%	extreme
September Weather	20°C (68°F)	1 mm (0.0 inches)	70%	very high
October Weather	17°C (63°F)	9 mm (0.3 inches)	70%	high
November Weather	14°C (57°F)	29 mm (1.1 inches)	74%	moderate
December Weather	11°C (51°F)	62 mm (2.4 inches)	76%	moderate