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September Weather in San Isidro, Mexico

Last updated: August 27, 2025

In September, the average temperature in San Isidro, Mexico is a pleasant 25°C (78°F). Temperatures can range from a minimum of 10°C (50°F) to a maximum of 37°C (100°F). With an average humidity of 74%, you can expect a bit of mugginess, but the beauty of the region shines through. Be prepared for some rain, as the area receives about 24 mm (1.0 in) of precipitation over 4 days.

September Temperature in San Isidro

In September in San Isidro, the average temperature is 25°C (78°F), with maximums reaching 37°C (100°F) and minimums dropping as low as 10°C (50°F). It's advisable to pack a variety of clothing to accommodate this range and enjoy your travels comfortably.

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 25°C (78°F), with highs reaching up to 37°C (100°F) and lows dropping to around 10°C (50°F).
JanFebMarAprMayJunJulAugSepOctNovDec465260697785848478685748
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 24 mm (1.0 in) over the course of 4 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 24 mm (1.0 inches) of precipitation spread over approximately 4 days.
JanFebMarAprMayJunJulAugSepOctNovDec1211184318272824211218
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 74%. With an average temperature of 25°C (78°F), this humidity feels like you're enveloped in a warm, thick blanket, making outdoor activities feel more strenuous and necessitating frequent breaks and hydration for comfortable travel.

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 74%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec81%77%65%53%51%51%60%63%74%75%83%87%
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.
JanFebMarAprMayJunJulAugSepOctNovDec5810121313131211965
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 Weather8°C (46°F)12 mm (0.5 inches)81%moderate
February Weather11°C (52°F)11 mm (0.4 inches)77%very high
March Weather16°C (60°F)18 mm (0.7 inches)65%very high
April Weather21°C (69°F)4 mm (0.2 inches)53%extreme
May Weather25°C (77°F)3 mm (0.1 inches)51%extreme
June Weather29°C (85°F)18 mm (0.7 inches)51%extreme
July Weather29°C (85°F)27 mm (1.0 inches)60%extreme
August Weather29°C (84°F)28 mm (1.1 inches)63%extreme
September Weather25°C (78°F)24 mm (1.0 inches)74%extreme
October Weather20°C (68°F)21 mm (0.8 inches)75%very high
November Weather14°C (57°F)12 mm (0.5 inches)82%high
December Weather9°C (48°F)17 mm (0.7 inches)87%moderate

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