September Weather in Santiago, Mexico

Last updated: August 27, 2025

In September, the average temperature in Santiago, Mexico hovers around 23°C (74°F), providing a pleasant climate for visitors. Expect minimum temperatures of 19°C (66°F) and maximums reaching 30°C (86°F). Rainfall is significant, with an average of 453 mm (17.9 in) spread over 29 days, resulting in a humidity level of about 78%. This blend of warmth and moisture creates a unique atmosphere, perfect for exploration!

September Temperature in Santiago

In September in Santiago, the average temperature is 23°C (74°F), with maximums reaching 30°C (86°F) and minimums dropping as low as 19°C (66°F). This pleasant climate makes Santiago an ideal destination for travelers looking to enjoy mild and comfortable weather.

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

The chart illustrates September temperature patterns in Santiago, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Santiago, September typically has an average temperature of 23°C (74°F), with highs reaching up to 30°C (86°F) and lows dropping to around 19°C (66°F).

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

September Precipitation in Santiago

In Santiago in September, the precipitation amount is 453 mm (17.9 in) over a span of 29 days.

September Precipitation Trends in Santiago

The chart displays monthly precipitation patterns in Santiago, 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 Santiago, September typically receives around 453 mm (17.9 inches) of precipitation spread over approximately 29 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 Santiago

In Santiago in September humidity is 78%. With an average temperature of 23°C (74°F), this humidity feels like a warm, enveloping embrace, making travel somewhat stifling and prompting frequent breaks to hydrate and seek shade.

September Average Humidity in Santiago

This chart illustrates the average monthly humidity levels in Santiago, 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 Santiago is approximately 78%, 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 Santiago

In Santiago in September, the maximum UV index reaches 13, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's crucial to take protective measures. For detailed information, you can check the Hourly UV Index in Santiago.

Maximum UV Index Levels in Santiago for September

The chart shows the monthly maximum UV Index (UVI) for Santiago 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 Santiago typically reaches 13, which falls under the extreme exposure category.

Data source: Santiago 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 Santiago Compares to Other Months

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

This table compares monthly weather conditions in Santiago, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	21°C (70°F)	12 mm (0.5 inches)	66%	very high
February Weather	22°C (71°F)	8 mm (0.3 inches)	64%	extreme
March Weather	23°C (73°F)	9 mm (0.3 inches)	63%	extreme
April Weather	23°C (74°F)	6 mm (0.3 inches)	69%	extreme
May Weather	24°C (76°F)	95 mm (3.7 inches)	73%	extreme
June Weather	23°C (74°F)	391 mm (15.4 inches)	76%	extreme
July Weather	24°C (75°F)	302 mm (11.9 inches)	78%	extreme
August Weather	23°C (75°F)	426 mm (16.8 inches)	79%	extreme
September Weather	23°C (74°F)	453 mm (17.9 inches)	78%	extreme
October Weather	23°C (74°F)	336 mm (13.2 inches)	75%	extreme
November Weather	22°C (73°F)	92 mm (3.6 inches)	72%	very high
December Weather	21°C (71°F)	23 mm (0.9 inches)	70%	very high