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September Weather in San Jose, Mexico

Last updated: August 27, 2025

In September, the average temperature in San Jose, Mexico hovers around 28°C (83°F), with a comfortable minimum of 23°C (74°F) and a sizzling maximum reaching 37°C (100°F). However, prepare yourself for some rain, as 219 mm (8.6 in) of precipitation falls over approximately 24 days, accompanied by an average humidity of 80%. Enjoy the tropical vibes, but don’t forget your umbrella!

September Temperature in San Jose

In September in San Jose, the average temperature is 28°C (83°F). Maximums can reach 37°C (100°F), and minimums can be as low as 23°C (74°F). This climate makes San Jose an inviting destination for travelers seeking warm weather and outdoor activities.

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 28°C (83°F), with highs reaching up to 37°C (100°F) and lows dropping to around 23°C (74°F).
JanFebMarAprMayJunJulAugSepOctNovDec757881858884858483817775
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 precipitation amount is 219 mm (8.6 in) spread over a period of 24 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 219 mm (8.6 inches) of precipitation spread over approximately 24 days.
JanFebMarAprMayJunJulAugSepOctNovDec42211732742499014921925111849
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 80%. With an average temperature of 28°C (83°F), this humidity feels like a thick blanket enveloping you, making travel feel sluggish and sticky, as every movement generates a sheen of perspiration that clings to your skin.

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 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec79%73%64%61%60%59%64%76%80%82%83%84%
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 12, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, underscoring the importance of sun protection. For detailed information, you can check the Hourly UV Index in San Jose.

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 12, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec911131313141313121198
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 Weather24°C (75°F)42 mm (1.6 inches)78%very high
February Weather26°C (78°F)21 mm (0.8 inches)73%extreme
March Weather27°C (82°F)17 mm (0.7 inches)64%extreme
April Weather29°C (85°F)32 mm (1.3 inches)61%extreme
May Weather31°C (88°F)74 mm (2.9 inches)59%extreme
June Weather29°C (84°F)249 mm (9.8 inches)59%extreme
July Weather29°C (85°F)90 mm (3.5 inches)64%extreme
August Weather29°C (84°F)149 mm (5.9 inches)76%extreme
September Weather28°C (83°F)219 mm (8.6 inches)80%extreme
October Weather27°C (81°F)251 mm (9.9 inches)82%extreme
November Weather25°C (78°F)118 mm (4.7 inches)83%very high
December Weather24°C (76°F)49 mm (1.9 inches)84%very high

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