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September Weather in Rio Grande, Puerto Rico

Last updated: August 31, 2025

In September, the average temperature in Rio Grande, Puerto Rico is a pleasant 28°C (82°F), with minimums dipping to 25°C (77°F) and maximums rising to 31°C (89°F). Expect 154 mm (6.0 in) of precipitation over 24 days, contributing to an average humidity of 79%. Enjoy the warm, tropical climate while being prepared for the occasional rain!

September Temperature in Rio Grande

In September in Rio Grande, the average temperature is 28°C (82°F). Maximums can reach 31°C (89°F), while minimums can drop to as low as 25°C (77°F). This warm climate makes it a perfect destination for beach lovers and outdoor activities.

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 28°C (82°F), with highs reaching up to 31°C (89°F) and lows dropping to around 25°C (77°F).
JanFebMarAprMayJunJulAugSepOctNovDec777777788081828282818079
Data source: Temperature data for Rio Grande generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Rio Grande

In Rio Grande in September, the precipitation amount is 154 mm (6.0 in) spread over 24 days, indicating a relatively wet period for the region.

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 154 mm (6.0 inches) of precipitation spread over approximately 24 days.
JanFebMarAprMayJunJulAugSepOctNovDec49526355746911011115414111268
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Rio Grande

In Rio Grande in September humidity is 79%. With an average temperature of 28°C (82°F), this humidity feels like a warm blanket wrapping around you, making outdoor exploration more strenuous and requiring frequent breaks for hydration.

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 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%75%74%75%75%77%80%80%79%78%78%76%
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.
JanFebMarAprMayJunJulAugSepOctNovDec911131313131213141298
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.
 TemperaturePrecipitationHumidityUV
January Weather25°C (77°F)49 mm (1.9 inches)76%very high
February Weather25°C (77°F)52 mm (2.1 inches)75%extreme
March Weather25°C (77°F)63 mm (2.5 inches)74%extreme
April Weather26°C (78°F)55 mm (2.2 inches)75%extreme
May Weather26°C (80°F)74 mm (2.9 inches)75%extreme
June Weather27°C (81°F)69 mm (2.7 inches)77%extreme
July Weather28°C (82°F)110 mm (4.3 inches)80%extreme
August Weather28°C (82°F)111 mm (4.4 inches)80%extreme
September Weather28°C (82°F)154 mm (6.0 inches)79%extreme
October Weather27°C (82°F)140 mm (5.5 inches)78%extreme
November Weather27°C (80°F)112 mm (4.4 inches)78%very high
December Weather26°C (79°F)68 mm (2.7 inches)76%very high

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