September Weather in Santiago, Mexico

Last updated: August 27, 2025

In September, the average temperature in Santiago, Mexico hovers around 26°C (80°F), making it a warm retreat. Expect minimums of 19°C (67°F) and highs reaching up to 35°C (95°F). With an average precipitation of 175 mm (6.9 in) over 16 days, it’s wise to keep an umbrella handy. The air retains an average humidity of 74%, lending a distinct tropical feel to the atmosphere.

September Temperature in Santiago

In September in Santiago, the average temperature is 26°C (80°F). Maximum temperatures can reach 35°C (95°F) and minimums can drop as low as 19°C (67°F). This makes it an ideal time for travelers to enjoy outdoor activities while being prepared for both warm days and cooler evenings.

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 26°C (80°F), with highs reaching up to 35°C (95°F) and lows dropping to around 19°C (67°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 total precipitation amount is 175 mm (6.9 in) over the course of 16 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 175 mm (6.9 inches) of precipitation spread over approximately 16 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 74%. With an average temperature of 26°C (80°F), this humidity feels like a warm, thick blanket wrapping around you, making any outdoor activities feel more strenuous and sweat-inducing, so staying hydrated and taking frequent breaks in the shade is essential for enjoyable traveling.

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 74%, 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 is 12, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, underscoring the importance of sun protection. 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 12, 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	17°C (63°F)	10 mm (0.4 inches)	68%	high
February Weather	18°C (65°F)	14 mm (0.6 inches)	66%	very high
March Weather	20°C (69°F)	2 mm (0.1 inches)	65%	extreme
April Weather	23°C (73°F)	1 mm (0.0 inches)	63%	extreme
May Weather	25°C (77°F)	0 mm (0.0 inches)	63%	extreme
June Weather	28°C (83°F)	22 mm (0.9 inches)	66%	extreme
July Weather	28°C (84°F)	93 mm (3.7 inches)	71%	extreme
August Weather	28°C (83°F)	131 mm (5.2 inches)	73%	extreme
September Weather	26°C (80°F)	175 mm (6.9 inches)	74%	extreme
October Weather	25°C (78°F)	25 mm (1.0 inches)	73%	extreme
November Weather	22°C (72°F)	24 mm (0.9 inches)	71%	very high
December Weather	18°C (65°F)	14 mm (0.5 inches)	69%	high