September Weather in Castro, Brazil

Last updated: August 22, 2025

In September, the average temperature in Castro, Brazil is a comfortable 18°C (65°F). Expect a minimum of 7°C (44°F) and a maximum soaring to 31°C (89°F). With precipitation averaging 65 mm (2.6 in) over 6 days, it's wise to carry an umbrella. The average humidity sits at a pleasant 58%, making it a great time to explore the area!

September Temperature in Castro

In September in Castro, the average temperature is 18°C (65°F). The maximum can reach 31°C (89°F), while the minimum can drop to as low as 7°C (44°F). This moderate climate makes Castro an ideal destination for travelers seeking a comfortable and enjoyable experience.

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

The chart illustrates September temperature patterns in Castro, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Castro, September typically has an average temperature of 18°C (65°F), with highs reaching up to 31°C (89°F) and lows dropping to around 7°C (44°F).

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

September Precipitation in Castro

In Castro, in September, the precipitation amount is 65 mm (2.6 in) over a period of 6 days.

September Precipitation Trends in Castro

The chart displays monthly precipitation patterns in Castro, 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 Castro, September typically receives around 65 mm (2.6 inches) of precipitation spread over approximately 6 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 Castro

In Castro in September humidity is 58%. With an average temperature of 18°C (65°F), this humidity feels like a warm embrace, creating a comfortable yet slightly muggy atmosphere perfect for leisurely exploration.

September Average Humidity in Castro

This chart illustrates the average monthly humidity levels in Castro, 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 Castro is approximately 58%, 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 Castro

In Castro 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 Castro.

Maximum UV Index Levels in Castro for September

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

Data source: Castro 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 Castro Compares to Other Months

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

This table compares monthly weather conditions in Castro, 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)	193 mm (7.6 inches)	85%	extreme
February Weather	21°C (70°F)	136 mm (5.3 inches)	80%	extreme
March Weather	20°C (69°F)	132 mm (5.2 inches)	80%	extreme
April Weather	18°C (65°F)	49 mm (1.9 inches)	77%	extreme
May Weather	16°C (61°F)	74 mm (2.9 inches)	76%	very high
June Weather	15°C (59°F)	102 mm (4.0 inches)	74%	high
July Weather	14°C (57°F)	28 mm (1.1 inches)	66%	high
August Weather	15°C (59°F)	74 mm (2.9 inches)	57%	very high
September Weather	18°C (65°F)	65 mm (2.6 inches)	58%	extreme
October Weather	19°C (66°F)	166 mm (6.5 inches)	60%	extreme
November Weather	19°C (67°F)	106 mm (4.2 inches)	78%	extreme
December Weather	21°C (69°F)	176 mm (6.9 inches)	86%	extreme