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September Weather in Stella, Puerto Rico

Last updated: August 31, 2025

In September, the average temperature in Stella, Puerto Rico is a warm 28°C (82°F), with a pleasant range between a minimum of 25°C (78°F) and a maximum of 31°C (87°F). However, prepare for some rainy days, as 141 mm (5.5 in) of precipitation can be expected over approximately 18 days. The air is often quite humid, with an average humidity of 79%, adding to the tropical feel of the season.

September Temperature in Stella

In September in Stella, the average temperature is 28°C (82°F). The maximum can reach 31°C (87°F), while the minimum can be as low as 25°C (78°F). Overall, this pleasant climate makes Stella a perfect destination for travelers seeking warm weather and outdoor activities.

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

The chart illustrates September temperature patterns in Stella, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Stella, September typically has an average temperature of 28°C (82°F), with highs reaching up to 31°C (87°F) and lows dropping to around 25°C (78°F).
JanFebMarAprMayJunJulAugSepOctNovDec777777788081828282818079
Data source: Temperature data for Stella 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 Stella

In Stella in September, the total precipitation amount is 141 mm (5.5 in) over the course of 18 days.

September Precipitation Trends in Stella

The chart displays monthly precipitation patterns in Stella, 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 Stella, September typically receives around 141 mm (5.5 inches) of precipitation spread over approximately 18 days.
JanFebMarAprMayJunJulAugSepOctNovDec1721383949486964141716620
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Stella

In Stella 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 Stella

This chart illustrates the average monthly humidity levels in Stella, 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 Stella 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 Stella

In Stella 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 Stella.

Maximum UV Index Levels in Stella for September

The chart shows the monthly maximum UV Index (UVI) for Stella 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 Stella typically reaches 13, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec911131314131313131298
Data source: Stella 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 Stella Compares to Other Months

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

This table compares monthly weather conditions in Stella, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather25°C (78°F)16 mm (0.6 inches)76%very high
February Weather25°C (77°F)21 mm (0.8 inches)75%extreme
March Weather25°C (77°F)38 mm (1.5 inches)74%extreme
April Weather26°C (78°F)39 mm (1.5 inches)75%extreme
May Weather26°C (80°F)49 mm (1.9 inches)75%extreme
June Weather27°C (81°F)48 mm (1.9 inches)77%extreme
July Weather28°C (82°F)69 mm (2.7 inches)80%extreme
August Weather28°C (82°F)64 mm (2.5 inches)80%extreme
September Weather28°C (82°F)141 mm (5.5 inches)79%extreme
October Weather27°C (81°F)71 mm (2.8 inches)78%extreme
November Weather27°C (80°F)66 mm (2.6 inches)78%very high
December Weather26°C (79°F)19 mm (0.8 inches)76%very high

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