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September Weather in San Guillermo, Mexico

Last updated: August 27, 2025

In September, the average temperature in San Guillermo, Mexico hovers around 22°C (73°F). Expect a comfortable range where the minimum can dip to 11°C (52°F) while highs might reach up to 34°C (93°F). Be prepared for some rain, as the area sees about 87 mm (3.4 in) of precipitation over 13 days, contributing to a fairly high average humidity of 79%.

September Temperature in San Guillermo

In September in San Guillermo, the average temperature is 22°C (73°F). Maximums can reach 34°C (93°F), while minimums can drop as low as 11°C (52°F). This makes San Guillermo a pleasant destination for travelers seeking comfortable weather.

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

The chart illustrates September temperature patterns in San Guillermo, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Guillermo, September typically has an average temperature of 22°C (73°F), with highs reaching up to 34°C (93°F) and lows dropping to around 11°C (52°F).
JanFebMarAprMayJunJulAugSepOctNovDec515663707782797872675951
Data source: Temperature data for San Guillermo 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 Guillermo

In San Guillermo in September, the precipitation amount is 87 mm (3.4 in) spread over 13 days.

September Precipitation Trends in San Guillermo

The chart displays monthly precipitation patterns in San Guillermo, 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 Guillermo, September typically receives around 87 mm (3.4 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec6545630796687341418
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in San Guillermo

In San Guillermo in September, humidity is 79%. With an average temperature of 22°C (73°F), this humidity feels like a warm, muggy embrace that makes outdoor activities feel more taxing, and a quick stroll can leave you feeling slightly sticky and ready for a refreshing break.

September Average Humidity in San Guillermo

This chart illustrates the average monthly humidity levels in San Guillermo, 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 Guillermo is approximately 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec78%71%60%52%49%50%65%70%79%77%83%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in San Guillermo

In San Guillermo 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 Guillermo.

Maximum UV Index Levels in San Guillermo for September

The chart shows the monthly maximum UV Index (UVI) for San Guillermo 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 Guillermo typically reaches 12, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec69111313131313121086
Data source: San Guillermo 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 Guillermo Compares to Other Months

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

This table compares monthly weather conditions in San Guillermo, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather10°C (51°F)6 mm (0.2 inches)78%high
February Weather13°C (56°F)5 mm (0.2 inches)71%very high
March Weather17°C (63°F)4 mm (0.2 inches)60%extreme
April Weather21°C (70°F)5 mm (0.2 inches)52%extreme
May Weather25°C (77°F)6 mm (0.2 inches)49%extreme
June Weather28°C (83°F)30 mm (1.2 inches)50%extreme
July Weather26°C (79°F)79 mm (3.1 inches)65%extreme
August Weather25°C (78°F)66 mm (2.6 inches)70%extreme
September Weather22°C (73°F)87 mm (3.4 inches)79%extreme
October Weather19°C (67°F)34 mm (1.3 inches)77%very high
November Weather15°C (60°F)14 mm (0.6 inches)83%very high
December Weather11°C (51°F)18 mm (0.7 inches)84%high

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