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September Weather in San Sebastian, Philippines

Last updated: August 27, 2025

In September, the average temperature in San Sebastian, Philippines hovers around 28°C (82°F). Daily highs can reach 31°C (88°F), while lows typically drop to 25°C (77°F). However, be prepared for frequent rain, with an average precipitation of 298 mm (11.7 in) spread over 21 days. With an average humidity of 87%, the atmosphere is certainly tropical, making it a vibrant destination for travelers.

September Temperature in San Sebastian

In September in San Sebastian, the average temperature is 28°C (82°F), with maximums reaching up to 31°C (88°F) and minimums dipping as low as 25°C (77°F). This warm climate makes San Sebastian an ideal destination for travelers seeking pleasant weather.

September Weather in San Sebastian: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in San Sebastian, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Sebastian, September typically has an average temperature of 28°C (82°F), with highs reaching up to 31°C (88°F) and lows dropping to around 25°C (77°F).
JanFebMarAprMayJunJulAugSepOctNovDec797981828483828282838281
Data source: Temperature data for San Sebastian 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 San Sebastian

In San Sebastian in September, the total precipitation amount is 298 mm (11.7 in) over the course of 21 days.

September Precipitation Trends in San Sebastian

The chart displays monthly precipitation patterns in San Sebastian, 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 San Sebastian, September typically receives around 298 mm (11.7 inches) of precipitation spread over approximately 21 days.
JanFebMarAprMayJunJulAugSepOctNovDec27135111443755616782981705817
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in San Sebastian

In San Sebastian in September humidity is 87%. With an average temperature of 28°C (82°F), this humidity feels like a warm, thick blanket wrapping around you, making travel challenging as you navigate the air's heavy moisture.

September Average Humidity in San Sebastian

This chart illustrates the average monthly humidity levels in San Sebastian, 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 San Sebastian is approximately 87%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec77%73%71%73%77%85%86%87%87%86%89%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in San Sebastian

In San Sebastian 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 San Sebastian, you can check here.

Maximum UV Index Levels in San Sebastian for September

The chart shows the monthly maximum UV Index (UVI) for San Sebastian 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 San Sebastian typically reaches 14, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec10121414131314141413109
Data source: San Sebastian 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 San Sebastian Compares to Other Months

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

This table compares monthly weather conditions in San Sebastian, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather26°C (80°F)27 mm (1.1 inches)77%very high
February Weather26°C (79°F)13 mm (0.5 inches)73%extreme
March Weather27°C (81°F)5 mm (0.2 inches)71%extreme
April Weather28°C (83°F)11 mm (0.4 inches)73%extreme
May Weather29°C (84°F)144 mm (5.7 inches)77%extreme
June Weather29°C (84°F)375 mm (14.7 inches)85%extreme
July Weather28°C (83°F)561 mm (22.1 inches)86%extreme
August Weather28°C (82°F)678 mm (26.7 inches)87%extreme
September Weather28°C (82°F)298 mm (11.7 inches)87%extreme
October Weather28°C (83°F)170 mm (6.7 inches)86%extreme
November Weather28°C (83°F)58 mm (2.3 inches)89%very high
December Weather27°C (81°F)17 mm (0.7 inches)85%very high

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