September Weather in Rio Grande, Mexico

Last updated: August 27, 2025

In September, the average temperature in Rio Grande, Mexico hovers around 20°C (68°F), providing a pleasant climate for outdoor adventures. Expect a minimum of 11°C (53°F) and a maximum of 30°C (86°F) throughout the month. However, be prepared for some rain, as precipitation averages 175 mm (6.9 in) over 21 days. With an average humidity of 81%, the air can be quite humid, adding to the tropical allure of this charming destination.

September Temperature in Rio Grande

In September in Rio Grande, the average temperature is 20°C (68°F). The maximum can reach 30°C (86°F), and the minimum can be as low as 11°C (53°F). This mild climate makes it an ideal time for outdoor activities and exploring the local attractions.

September Weather in Rio Grande: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Rio Grande, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Rio Grande, September typically has an average temperature of 20°C (68°F), with highs reaching up to 30°C (86°F) and lows dropping to around 11°C (53°F).

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

September Precipitation in Rio Grande

In Rio Grande in September, the precipitation amount reaches 175 mm (6.9 in) over the course of 21 days.

September Precipitation Trends in Rio Grande

The chart displays monthly precipitation patterns in Rio Grande, 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 Rio Grande, September typically receives around 175 mm (6.9 inches) of precipitation spread over approximately 21 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 Rio Grande

In Rio Grande in September humidity is 81%. With an average temperature of 20°C (68°F), this humidity feels like a warm embrace that can make outdoor activities feel steamy and exhausting, potentially leading travelers to seek shade or a refreshing drink more often.

September Average Humidity in Rio Grande

This chart illustrates the average monthly humidity levels in Rio Grande, 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 Rio Grande 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 Rio Grande

In Rio Grande 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 Rio Grande, you can check here.

Maximum UV Index Levels in Rio Grande for September

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

Data source: Rio Grande 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 Rio Grande Compares to Other Months

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

This table compares monthly weather conditions in Rio Grande, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	16°C (60°F)	6 mm (0.2 inches)	74%	very high
February Weather	18°C (64°F)	10 mm (0.4 inches)	65%	extreme
March Weather	21°C (69°F)	6 mm (0.2 inches)	58%	extreme
April Weather	22°C (73°F)	3 mm (0.1 inches)	58%	extreme
May Weather	24°C (75°F)	31 mm (1.2 inches)	67%	extreme
June Weather	22°C (72°F)	145 mm (5.7 inches)	76%	extreme
July Weather	20°C (68°F)	203 mm (8.0 inches)	67%	extreme
August Weather	20°C (68°F)	175 mm (6.9 inches)	68%	extreme
September Weather	20°C (68°F)	175 mm (6.9 inches)	81%	extreme
October Weather	19°C (67°F)	65 mm (2.6 inches)	83%	extreme
November Weather	17°C (64°F)	24 mm (0.9 inches)	84%	very high
December Weather	15°C (60°F)	3 mm (0.1 inches)	81%	very high