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September Weather in San Pedro, Costa Rica

Last updated: August 23, 2025

In San Pedro, Costa Rica, the average temperature in September hovers around 19°C (66°F), with a comfortable range from a minimum of 14°C (58°F) to a maximum of 25°C (78°F). Expect heavy rainfall during this month, with about 379 mm (14.9 in) of precipitation spread across 29 days. Coupled with an average humidity of 81%, it's wise to prepare for a humid and often wet experience.

September Temperature in San Pedro

In September in San Pedro, the average temperature is 19°C (66°F). The maximum can reach 25°C (78°F), while the minimum can be as low as 14°C (58°F). This mild weather makes it an ideal time for outdoor exploration and sightseeing.

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

The chart illustrates September temperature patterns in San Pedro, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Pedro, September typically has an average temperature of 19°C (66°F), with highs reaching up to 25°C (78°F) and lows dropping to around 14°C (58°F).
JanFebMarAprMayJunJulAugSepOctNovDec636364666666666666656564
Data source: Temperature data for San Pedro 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 Pedro

In San Pedro in September, the precipitation amount is 379 mm (14.9 in) that falls over a duration of 29 days.

September Precipitation Trends in San Pedro

The chart displays monthly precipitation patterns in San Pedro, 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 Pedro, September typically receives around 379 mm (14.9 inches) of precipitation spread over approximately 29 days.
JanFebMarAprMayJunJulAugSepOctNovDec934349113425341266304380517260156
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in San Pedro

In San Pedro in September, humidity is 81%. With an average temperature of 19°C (66°F), this humidity feels like a warm, heavy blanket enveloping you, making travel feel both muggy and slightly stifling, often leading to a need for frequent breaks in the shade.

September Average Humidity in San Pedro

This chart illustrates the average monthly humidity levels in San Pedro, 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 Pedro is approximately 81%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec68%68%66%67%69%84%85%82%81%80%80%73%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in San Pedro

In San Pedro 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 Pedro, you can check here.

Maximum UV Index Levels in San Pedro for September

The chart shows the monthly maximum UV Index (UVI) for San Pedro 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 Pedro typically reaches 14, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec121415161414141414151211
Data source: San Pedro 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 Pedro Compares to Other Months

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

This table compares monthly weather conditions in San Pedro, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather17°C (63°F)93 mm (3.7 inches)68%extreme
February Weather17°C (64°F)43 mm (1.7 inches)68%extreme
March Weather18°C (64°F)49 mm (1.9 inches)66%extreme
April Weather19°C (66°F)113 mm (4.4 inches)67%extreme
May Weather19°C (67°F)425 mm (16.7 inches)69%extreme
June Weather19°C (67°F)341 mm (13.4 inches)84%extreme
July Weather19°C (66°F)266 mm (10.5 inches)85%extreme
August Weather19°C (66°F)304 mm (12.0 inches)82%extreme
September Weather19°C (66°F)379 mm (14.9 inches)81%extreme
October Weather19°C (66°F)517 mm (20.4 inches)80%extreme
November Weather18°C (65°F)260 mm (10.3 inches)80%extreme
December Weather18°C (64°F)156 mm (6.1 inches)72%extreme

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