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September Weather in San Mateo, Mexico

Last updated: August 27, 2025

In September, the average temperature in San Mateo, Mexico hovers around a warm 27°C (81°F). You can expect temperatures to dip to a minimum of 23°C (74°F) and peak at a sweltering 33°C (91°F). Additionally, be prepared for 253 mm (10.0 in) of precipitation spread across 23 days, contributing to an average humidity level of 73%.

September Temperature in San Mateo

In September in San Mateo, the average temperature is 27°C (81°F), with maximums reaching 33°C (91°F) and minimums dropping to 23°C (74°F). This mild climate makes it a perfect time for outdoor adventures and exploration.

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

The chart illustrates September temperature patterns in San Mateo, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Mateo, September typically has an average temperature of 27°C (81°F), with highs reaching up to 33°C (91°F) and lows dropping to around 23°C (74°F).
JanFebMarAprMayJunJulAugSepOctNovDec737373727580828180807875
Data source: Temperature data for San Mateo 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 Mateo

In San Mateo in September, the precipitation amount is 253 mm (10.0 in) over a span of 23 days.

September Precipitation Trends in San Mateo

The chart displays monthly precipitation patterns in San Mateo, 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 Mateo, September typically receives around 253 mm (10.0 inches) of precipitation spread over approximately 23 days.
JanFebMarAprMayJunJulAugSepOctNovDec1419001116100272253174268
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in San Mateo

In San Mateo in September, humidity is 73%. With an average temperature of 27°C (81°F), this humidity feels like a warm blanket enveloping you, making outdoor activities feel sticky and heavy, while also requiring frequent hydration breaks to stay comfortable during your travels.

September Average Humidity in San Mateo

This chart illustrates the average monthly humidity levels in San Mateo, 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 Mateo is approximately 73%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec68%70%71%72%73%74%73%74%73%72%69%70%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in San Mateo

In San Mateo in September, the maximum UV index reaches 13, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's crucial to take protective measures. For detailed information, you can check the Hourly UV Index in San Mateo.

Maximum UV Index Levels in San Mateo for September

The chart shows the monthly maximum UV Index (UVI) for San Mateo 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 Mateo typically reaches 13, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec810131313131213131297
Data source: San Mateo 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 Mateo Compares to Other Months

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

This table compares monthly weather conditions in San Mateo, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather23°C (74°F)14 mm (0.6 inches)68%very high
February Weather23°C (73°F)19 mm (0.7 inches)70%very high
March Weather23°C (73°F)0 mm (0.0 inches)70%extreme
April Weather22°C (73°F)0 mm (0.0 inches)72%extreme
May Weather24°C (76°F)1 mm (0.1 inches)73%extreme
June Weather26°C (80°F)116 mm (4.6 inches)74%extreme
July Weather28°C (82°F)100 mm (3.9 inches)73%extreme
August Weather27°C (82°F)272 mm (10.7 inches)74%extreme
September Weather27°C (81°F)253 mm (10.0 inches)73%extreme
October Weather27°C (80°F)174 mm (6.8 inches)72%extreme
November Weather25°C (78°F)26 mm (1.0 inches)69%very high
December Weather24°C (75°F)8 mm (0.3 inches)70%high

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