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September Weather in San Isidro, Mexico

Last updated: August 27, 2025

In San Isidro, Mexico during September, the average temperature is a warm 28°C (82°F). Temperatures can range from a comfortable 18°C (64°F) to a sizzling 39°C (103°F). Expect about 125 mm (4.9 in) of precipitation across 11 days, with an average humidity level of 75%, making for a vibrant yet humid atmosphere.

September Temperature in San Isidro

In September in San Isidro, the average temperature is 28°C (82°F), with maximums reaching up to 39°C (103°F) and minimums dipping as low as 18°C (64°F), making it an ideal time for travelers who enjoy warm weather and outdoor activities.

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

The chart illustrates September temperature patterns in San Isidro, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Isidro, September typically has an average temperature of 28°C (82°F), with highs reaching up to 39°C (103°F) and lows dropping to around 18°C (64°F).
JanFebMarAprMayJunJulAugSepOctNovDec606472778385868882756763
Data source: Temperature data for San Isidro 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 Isidro

In San Isidro in September, the precipitation amount is 125 mm (4.9 in) over the course of 11 days.

September Precipitation Trends in San Isidro

The chart displays monthly precipitation patterns in San Isidro, 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 Isidro, September typically receives around 125 mm (4.9 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec24132647761079317125502418
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in San Isidro

In San Isidro in September humidity is 75%. With an average temperature of 28°C (82°F), this humidity feels like a warm, enveloping embrace that can quickly leave travelers feeling sticky and fatigued. It can make outdoor activities challenging, as sweat doesn’t evaporate easily, leading to a constant struggle between comfort and the desire to explore.

September Average Humidity in San Isidro

This chart illustrates the average monthly humidity levels in San Isidro, 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 Isidro is approximately 75%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%83%78%81%82%74%68%67%75%78%83%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in San Isidro

In San Isidro in September, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in San Isidro.

Maximum UV Index Levels in San Isidro for September

The chart shows the monthly maximum UV Index (UVI) for San Isidro 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 Isidro typically reaches 11, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec68101212121212111076
Data source: San Isidro 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 Isidro Compares to Other Months

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

This table compares monthly weather conditions in San Isidro, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather16°C (60°F)24 mm (0.9 inches)84%high
February Weather18°C (65°F)13 mm (0.5 inches)83%very high
March Weather22°C (72°F)26 mm (1.0 inches)78%very high
April Weather25°C (77°F)47 mm (1.9 inches)81%extreme
May Weather28°C (83°F)76 mm (3.0 inches)82%extreme
June Weather30°C (85°F)106 mm (4.2 inches)74%extreme
July Weather30°C (87°F)93 mm (3.7 inches)68%extreme
August Weather31°C (88°F)17 mm (0.7 inches)67%extreme
September Weather28°C (82°F)125 mm (4.9 inches)75%extreme
October Weather24°C (76°F)50 mm (2.0 inches)78%very high
November Weather20°C (67°F)24 mm (0.9 inches)83%high
December Weather17°C (63°F)18 mm (0.7 inches)86%high

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