September Weather in Altar, Mexico

Last updated: August 27, 2025

In September, the average temperature in Altar, Mexico hovers around 30°C (86°F). However, visitors should be prepared for a range, as temperatures can dip to a minimum of 14°C (58°F) and soar up to a maximum of 43°C (109°F). Expect a touch of moisture in the air, with an average humidity level of 72% and precipitation totaling 41 mm (1.6 in) over approximately 5 days.

September Temperature in Altar

In September, in Altar, the average temperature is 30°C (86°F). Maximum temperatures can reach up to 43°C (109°F), while minimums can drop to as low as 14°C (58°F). Be prepared for a wide range of temperatures, making it wise to pack both light clothing and warmer layers for your trip.

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

The chart illustrates September temperature patterns in Altar, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Altar, September typically has an average temperature of 30°C (86°F), with highs reaching up to 43°C (109°F) and lows dropping to around 14°C (58°F).

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

September Precipitation in Altar

In Altar in September, the precipitation amount is 41 mm (1.6 in) over a period of 5 days.

September Precipitation Trends in Altar

The chart displays monthly precipitation patterns in Altar, 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 Altar, September typically receives around 41 mm (1.6 inches) of precipitation spread over approximately 5 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 Altar

In Altar in September humidity is 72%. With an average temperature of 30°C (86°F), this humidity feels like walking through a warm, thick blanket, making travel feel heavy and sluggish, and potentially tiring if you're not adequately prepared for the mugginess.

September Average Humidity in Altar

This chart illustrates the average monthly humidity levels in Altar, 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 Altar is approximately 72%, 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 Altar

In Altar in September, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Altar.

Maximum UV Index Levels in Altar for September

The chart shows the monthly maximum UV Index (UVI) for Altar 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 Altar typically reaches 11, which falls under the extreme exposure category.

Data source: Altar 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 Altar Compares to Other Months

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

This table compares monthly weather conditions in Altar, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	14°C (57°F)	22 mm (0.9 inches)	74%	moderate
February Weather	15°C (59°F)	26 mm (1.0 inches)	71%	high
March Weather	18°C (65°F)	14 mm (0.6 inches)	60%	very high
April Weather	23°C (74°F)	2 mm (0.1 inches)	43%	extreme
May Weather	26°C (79°F)	2 mm (0.1 inches)	32%	extreme
June Weather	32°C (89°F)	3 mm (0.1 inches)	28%	extreme
July Weather	32°C (90°F)	43 mm (1.7 inches)	38%	extreme
August Weather	32°C (90°F)	38 mm (1.5 inches)	60%	extreme
September Weather	30°C (86°F)	41 mm (1.6 inches)	72%	extreme
October Weather	25°C (77°F)	9 mm (0.3 inches)	66%	very high
November Weather	20°C (68°F)	19 mm (0.8 inches)	74%	high
December Weather	15°C (58°F)	17 mm (0.7 inches)	81%	moderate