September Weather in Castanhal, Brazil

Last updated: August 22, 2025

In Castanhal, Brazil, the average temperature in September is a warm 28°C (82°F). During this time, you can expect a pleasant range, with minimum temperatures dropping to 21°C (71°F) and soaring up to a maximum of 36°C (96°F). However, be prepared for some rain, as 53 mm (2.1 in) of precipitation is expected over approximately 13 days. With an average humidity of 69%, it's the perfect time to enjoy everything this vibrant destination has to offer!

September Temperature in Castanhal

In September in Castanhal, the average temperature is 28°C (82°F). Maximums can reach 36°C (96°F), while minimums can drop to as low as 21°C (71°F). This makes it an ideal time for travelers to enjoy warm weather and outdoor activities.

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

The chart illustrates September temperature patterns in Castanhal, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Castanhal, September typically has an average temperature of 28°C (82°F), with highs reaching up to 36°C (96°F) and lows dropping to around 21°C (71°F).

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

September Precipitation in Castanhal

In Castanhal in September, the precipitation amount is 53 mm (2.1 in) over the course of 13 days.

September Precipitation Trends in Castanhal

The chart displays monthly precipitation patterns in Castanhal, 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 Castanhal, September typically receives around 53 mm (2.1 inches) of precipitation spread over approximately 13 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 Castanhal

In Castanhal in September, humidity is 69%. With an average temperature of 28°C (82°F), this humidity feels like a warm embrace that clings to your skin, making outdoor exploration slightly more challenging but still enjoyable as you soak in the vibrant surroundings.

September Average Humidity in Castanhal

This chart illustrates the average monthly humidity levels in Castanhal, 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 Castanhal is approximately 69%, 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 Castanhal

In Castanhal in September, the maximum UV index reaches 13, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's crucial to take protective measures. For detailed information, you can check the Hourly UV Index in Castanhal.

Maximum UV Index Levels in Castanhal for September

The chart shows the monthly maximum UV Index (UVI) for Castanhal 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 Castanhal typically reaches 13, which falls under the extreme exposure category.

Data source: Castanhal 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 Castanhal Compares to Other Months

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

This table compares monthly weather conditions in Castanhal, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	26°C (79°F)	265 mm (10.4 inches)	89%	extreme
February Weather	26°C (79°F)	525 mm (20.7 inches)	81%	extreme
March Weather	26°C (79°F)	535 mm (21.1 inches)	81%	extreme
April Weather	26°C (79°F)	445 mm (17.5 inches)	85%	extreme
May Weather	26°C (80°F)	350 mm (13.8 inches)	89%	extreme
June Weather	27°C (80°F)	132 mm (5.2 inches)	86%	extreme
July Weather	27°C (80°F)	86 mm (3.4 inches)	81%	extreme
August Weather	27°C (81°F)	56 mm (2.2 inches)	72%	extreme
September Weather	28°C (82°F)	53 mm (2.1 inches)	69%	extreme
October Weather	28°C (83°F)	58 mm (2.3 inches)	69%	extreme
November Weather	28°C (82°F)	98 mm (3.9 inches)	71%	extreme
December Weather	27°C (81°F)	202 mm (8.0 inches)	82%	extreme