September Weather in Sao Luis, Portugal

Last updated: August 27, 2025

The average temperature in Sao Luis, Portugal during September hovers around 21°C (70°F). While you can expect a comfortable minimum of 12°C (54°F), the mercury can rise to a warm 33°C (92°F) on hotter days. With an average precipitation of just 11 mm (0.4 in) spread over 2 days, and an average humidity of 71%, it's a delightful time to explore!

September Temperature in Sao Luis

In September in Sao Luis, the average temperature is 21°C (70°F). The maximum can reach 33°C (92°F), and the minimum can be as low as 12°C (54°F). This makes it an ideal time for travelers looking to enjoy pleasant weather while exploring the region.

September Weather in Sao Luis: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Sao Luis, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sao Luis, September typically has an average temperature of 21°C (70°F), with highs reaching up to 33°C (92°F) and lows dropping to around 12°C (54°F).

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

September Precipitation in Sao Luis

In Sao Luis in September, the precipitation amount is 11 mm (0.4 in) over the course of 2 days.

September Precipitation Trends in Sao Luis

The chart displays monthly precipitation patterns in Sao Luis, 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 Sao Luis, September typically receives around 11 mm (0.4 inches) of precipitation spread over approximately 2 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 Sao Luis

In Sao Luis in September, humidity is 71%. With an average temperature of 21°C (70°F), this humidity feels like a warm, sticky embrace, making outdoor activities feel slightly heavy and requiring regular breaks to stay refreshed while exploring.

September Average Humidity in Sao Luis

This chart illustrates the average monthly humidity levels in Sao Luis, 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 Sao Luis is approximately 71%, 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 Sao Luis

In Sao Luis in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Sao Luis.

Maximum UV Index Levels in Sao Luis for September

The chart shows the monthly maximum UV Index (UVI) for Sao Luis 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 Sao Luis typically reaches 9, which falls under the very high exposure category.

Data source: Sao Luis 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 Sao Luis Compares to Other Months

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

This table compares monthly weather conditions in Sao Luis, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	11°C (52°F)	29 mm (1.1 inches)	80%	moderate
February Weather	13°C (55°F)	54 mm (2.1 inches)	73%	moderate
March Weather	14°C (57°F)	83 mm (3.3 inches)	71%	high
April Weather	15°C (60°F)	66 mm (2.6 inches)	69%	very high
May Weather	18°C (65°F)	23 mm (0.9 inches)	69%	very high
June Weather	19°C (67°F)	10 mm (0.4 inches)	67%	extreme
July Weather	21°C (70°F)	3 mm (0.1 inches)	69%	very high
August Weather	22°C (71°F)	2 mm (0.1 inches)	68%	very high
September Weather	21°C (70°F)	11 mm (0.4 inches)	71%	very high
October Weather	19°C (66°F)	45 mm (1.8 inches)	75%	high
November Weather	15°C (59°F)	58 mm (2.3 inches)	78%	moderate
December Weather	13°C (55°F)	51 mm (2.0 inches)	81%	moderate