September Weather in San Jose, Argentina

Last updated: August 22, 2025

In September, the average temperature in San Jose, Argentina reaches a pleasant 20°C (68°F). While you might enjoy sunny days with a high of 36°C (98°F), be prepared for cooler moments as temperatures can dip to a minimum of 6°C (44°F). Rainfall is a possibility, with about 103 mm (4.1 in) expected over 10 days. The average humidity hovers around 54%, providing a comfortable atmosphere for your adventures!

September Temperature in San Jose

In September in San Jose, the average temperature is 20°C (68°F). Maximum temperatures can reach 36°C (98°F), while minimums can drop to as low as 6°C (44°F). This makes San Jose a versatile destination for travelers, offering the warmth of summer days and the coolness of brisk evenings.

September Weather in San Jose: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in San Jose, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Jose, September typically has an average temperature of 20°C (68°F), with highs reaching up to 36°C (98°F) and lows dropping to around 6°C (44°F).

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

September Precipitation in San Jose

In San Jose in September, the precipitation amount is 103 mm (4.1 in) over a span of 10 days.

September Precipitation Trends in San Jose

The chart displays monthly precipitation patterns in San Jose, 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 San Jose, September typically receives around 103 mm (4.1 inches) of precipitation spread over approximately 10 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 San Jose

In San Jose in September, humidity is 54%. With an average temperature of 20°C (68°F), this humidity feels like a pleasant embrace, making it quite comfortable for traveling and exploring the surroundings.

September Average Humidity in San Jose

This chart illustrates the average monthly humidity levels in San Jose, 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 San Jose is approximately 54%, 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 San Jose

In San Jose 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 San Jose.

Maximum UV Index Levels in San Jose for September

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

Data source: San Jose 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 San Jose Compares to Other Months

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

This table compares monthly weather conditions in San Jose, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	27°C (80°F)	168 mm (6.6 inches)	77%	extreme
February Weather	26°C (78°F)	106 mm (4.2 inches)	71%	extreme
March Weather	24°C (76°F)	135 mm (5.3 inches)	74%	extreme
April Weather	21°C (71°F)	123 mm (4.8 inches)	82%	very high
May Weather	18°C (64°F)	197 mm (7.8 inches)	82%	high
June Weather	16°C (62°F)	99 mm (3.9 inches)	73%	moderate
July Weather	16°C (60°F)	96 mm (3.8 inches)	67%	high
August Weather	17°C (63°F)	80 mm (3.2 inches)	49%	high
September Weather	20°C (68°F)	103 mm (4.1 inches)	54%	very high
October Weather	22°C (72°F)	152 mm (6.0 inches)	58%	extreme
November Weather	24°C (75°F)	143 mm (5.6 inches)	69%	extreme
December Weather	26°C (79°F)	93 mm (3.7 inches)	84%	extreme