nomadseason

September Weather in Porto Velho, Brazil

Last updated: August 22, 2025

In September, the average temperature in Porto Velho, Brazil hovers around 28°C (83°F). Temperatures can vary, with a minimum of 20°C (68°F) and peaking at a scorching 37°C (100°F). Expect about 82 mm (3.2 in) of precipitation over 13 days, while the air stays pleasantly dry with an average humidity of only 32%.

September Temperature in Porto Velho

In September in Porto Velho, the average temperature is 28°C (83°F), with maximums reaching up to 37°C (100°F) and minimums dipping as low as 20°C (68°F). This makes it an ideal time for travelers to enjoy warm weather and outdoor activities.

September Weather in Porto Velho: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Porto Velho, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Porto Velho, September typically has an average temperature of 28°C (83°F), with highs reaching up to 37°C (100°F) and lows dropping to around 20°C (68°F).
JanFebMarAprMayJunJulAugSepOctNovDec797879797979798182818079
Data source: Temperature data for Porto Velho generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Porto Velho

In Porto Velho in September, the total precipitation amount is 82 mm (3.2 in), occurring over the course of 13 days.

September Precipitation Trends in Porto Velho

The chart displays monthly precipitation patterns in Porto Velho, 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 Porto Velho, September typically receives around 82 mm (3.2 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec2683693152681192733182185277372
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Porto Velho

In Porto Velho in September humidity is 32%. With an average temperature of 28°C (83°F), this humidity feels like a warm, comfortable embrace, making it ideal for leisurely sightseeing and outdoor adventures.

September Average Humidity in Porto Velho

This chart illustrates the average monthly humidity levels in Porto Velho, 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 Porto Velho is approximately 32%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%85%86%89%85%76%53%36%32%36%64%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Porto Velho

In Porto Velho in September, the maximum UV index is 12, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, underscoring the importance of sun protection. For detailed information, you can check the Hourly UV Index in Porto Velho.

Maximum UV Index Levels in Porto Velho for September

The chart shows the monthly maximum UV Index (UVI) for Porto Velho 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 Porto Velho typically reaches 12, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec151516151210101112141514
Data source: Porto Velho 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 Porto Velho Compares to Other Months

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

This table compares monthly weather conditions in Porto Velho, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather26°C (79°F)268 mm (10.5 inches)87%extreme
February Weather26°C (79°F)369 mm (14.5 inches)85%extreme
March Weather26°C (79°F)315 mm (12.4 inches)86%extreme
April Weather26°C (79°F)268 mm (10.5 inches)89%extreme
May Weather26°C (79°F)119 mm (4.7 inches)85%extreme
June Weather26°C (79°F)27 mm (1.1 inches)76%very high
July Weather26°C (80°F)3 mm (0.1 inches)53%very high
August Weather27°C (81°F)31 mm (1.2 inches)36%extreme
September Weather28°C (83°F)82 mm (3.2 inches)32%extreme
October Weather27°C (81°F)185 mm (7.3 inches)36%extreme
November Weather27°C (80°F)277 mm (10.9 inches)64%extreme
December Weather26°C (79°F)372 mm (14.7 inches)85%extreme

Compare Porto Velho's Climate with Cities Worldwide