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September Weather in San Jose, Mexico

Last updated: August 27, 2025

In September, the average temperature in San Jose, Mexico is a pleasant 23°C (73°F). Expect comfortable minimums of 17°C (64°F) and warm maximums reaching 30°C (87°F). However, be prepared for 285 mm (11.2 in) of precipitation over approximately 28 days, with an average humidity level of 77%.

September Temperature in San Jose

In September in San Jose, the average temperature is 23°C (73°F), with maximums reaching 30°C (87°F) and minimums dropping to 17°C (64°F). This pleasant weather makes it an ideal time for travelers to explore and enjoy outdoor activities in San Jose.

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

The chart illustrates September temperature patterns in San Jose, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Jose, September typically has an average temperature of 23°C (73°F), with highs reaching up to 30°C (87°F) and lows dropping to around 17°C (64°F).
JanFebMarAprMayJunJulAugSepOctNovDec656769747673727373726866
Data source: Temperature data for San Jose 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 Jose

In San Jose in September, the total precipitation amount is 285 mm (11.2 in) spread over the course of 28 days.

September Precipitation Trends in San Jose

The chart displays monthly precipitation patterns in San Jose, 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 Jose, September typically receives around 285 mm (11.2 inches) of precipitation spread over approximately 28 days.
JanFebMarAprMayJunJulAugSepOctNovDec8047467920835917023528529214773
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in San Jose

In San Jose in September, humidity is 77%. With an average temperature of 23°C (73°F), this humidity feels like a warm, sticky embrace, making travel somewhat uncomfortable but bearable. It's essential to stay hydrated and take frequent breaks to enjoy the sights while avoiding overheating.

September Average Humidity in San Jose

This chart illustrates the average monthly humidity levels in San Jose, 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 Jose is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%73%59%53%54%55%61%71%77%78%82%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in San Jose

In San Jose 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 Jose, you can check here.

Maximum UV Index Levels in San Jose for September

The chart shows the monthly maximum UV Index (UVI) for San Jose 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 Jose typically reaches 14, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec10121414141414141413109
Data source: San Jose 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 Jose Compares to Other Months

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

This table compares monthly weather conditions in San Jose, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather18°C (65°F)80 mm (3.2 inches)84%very high
February Weather20°C (67°F)47 mm (1.9 inches)73%extreme
March Weather21°C (69°F)46 mm (1.8 inches)59%extreme
April Weather23°C (75°F)79 mm (3.1 inches)52%extreme
May Weather24°C (76°F)208 mm (8.2 inches)53%extreme
June Weather23°C (74°F)359 mm (14.1 inches)55%extreme
July Weather22°C (73°F)170 mm (6.7 inches)61%extreme
August Weather23°C (73°F)235 mm (9.2 inches)71%extreme
September Weather23°C (73°F)285 mm (11.2 inches)77%extreme
October Weather22°C (72°F)292 mm (11.5 inches)78%extreme
November Weather20°C (69°F)147 mm (5.8 inches)82%very high
December Weather19°C (66°F)73 mm (2.9 inches)86%very high

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