September Weather in San Isidro, Mexico

Last updated: August 27, 2025

In September, the average temperature in San Isidro, Mexico hovers around 18°C (65°F), with a comfortable range between a minimum of 8°C (47°F) and a maximum of 29°C (85°F). Expect about 125 mm (4.9 in) of precipitation spread over 17 days, contributing to an average humidity level of 81%. Stay prepared for a mix of weather conditions!

September Temperature in San Isidro

In September in San Isidro, the average temperature is 18°C (65°F), with maximums reaching 29°C (85°F) and minimums dropping as low as 8°C (47°F). This climate makes it an ideal time for travelers to enjoy pleasant outdoor activities.

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

The chart illustrates September temperature patterns in San Isidro, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Isidro, September typically has an average temperature of 18°C (65°F), with highs reaching up to 29°C (85°F) and lows dropping to around 8°C (47°F).

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

September Precipitation in San Isidro

In San Isidro in September, the precipitation amount is 125 mm (4.9 in) spread over 17 days.

September Precipitation Trends in San Isidro

The chart displays monthly precipitation patterns in San Isidro, 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 Isidro, September typically receives around 125 mm (4.9 inches) of precipitation spread over approximately 17 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 Isidro

In San Isidro in September, humidity is 81%. With an average temperature of 18°C (65°F), this humidity feels like a thick blanket wrapping around you, making every step feel heavier and the air thick and sultry—a challenging environment for traveling.

September Average Humidity in San Isidro

This chart illustrates the average monthly humidity levels in San Isidro, 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 Isidro is approximately 81%, 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 Isidro

In San Isidro in September, the maximum UV index is 14, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, so it's crucial to take precautions. For the detailed hourly UV index in San Isidro, you can check here.

Maximum UV Index Levels in San Isidro for September

The chart shows the monthly maximum UV Index (UVI) for San Isidro 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 Isidro typically reaches 14, which falls under the extreme exposure category.

Data source: San Isidro 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 Isidro Compares to Other Months

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

This table compares monthly weather conditions in San Isidro, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	13°C (56°F)	5 mm (0.2 inches)	74%	very high
February Weather	16°C (60°F)	7 mm (0.3 inches)	65%	extreme
March Weather	18°C (64°F)	10 mm (0.4 inches)	58%	extreme
April Weather	20°C (69°F)	11 mm (0.4 inches)	58%	extreme
May Weather	22°C (71°F)	35 mm (1.4 inches)	67%	extreme
June Weather	20°C (68°F)	139 mm (5.5 inches)	76%	extreme
July Weather	19°C (66°F)	103 mm (4.1 inches)	67%	extreme
August Weather	19°C (67°F)	89 mm (3.5 inches)	68%	extreme
September Weather	18°C (65°F)	125 mm (4.9 inches)	81%	extreme
October Weather	17°C (63°F)	61 mm (2.4 inches)	83%	extreme
November Weather	15°C (58°F)	19 mm (0.7 inches)	84%	very high
December Weather	13°C (56°F)	6 mm (0.2 inches)	81%	very high