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September Weather in Santa Monica, Mexico

Last updated: August 27, 2025

In Santa Monica, Mexico, the average temperature for September hovers around 18°C (64°F). Expect a pleasant range, with minimums dipping to 9°C (48°F) and maximums reaching up to 27°C (81°F). However, be prepared for some rain, as precipitation totals around 148 mm (5.8 in) spread over 17 days. With an average humidity of 86%, the air can feel quite moist, so pack accordingly!

September Temperature in Santa Monica

In September in Santa Monica, the average temperature is 18°C (64°F). The maximum can reach 27°C (81°F), while the minimum can drop to as low as 9°C (48°F). This pleasant climate makes Santa Monica an ideal destination for travelers seeking moderate weather and outdoor activities.

September Weather in Santa Monica: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Santa Monica, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Santa Monica, September typically has an average temperature of 18°C (64°F), with highs reaching up to 27°C (81°F) and lows dropping to around 9°C (48°F).
JanFebMarAprMayJunJulAugSepOctNovDec545763667069666664625854
Data source: Temperature data for Santa Monica 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 Santa Monica

In Santa Monica in September, the precipitation amount is 148 mm (5.8 in) spread over 17 days.

September Precipitation Trends in Santa Monica

The chart displays monthly precipitation patterns in Santa Monica, 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 Santa Monica, September typically receives around 148 mm (5.8 inches) of precipitation spread over approximately 17 days.
JanFebMarAprMayJunJulAugSepOctNovDec179672611014989148481612
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Santa Monica

In Santa Monica in September humidity is 86%. With an average temperature of 18°C (64°F), this humidity feels like a warm embrace, making travel slightly uncomfortable as the air becomes thick and sticky, often leading to clammy skin and a constant need for hydration.

September Average Humidity in Santa Monica

This chart illustrates the average monthly humidity levels in Santa Monica, 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 Santa Monica is approximately 86%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec71%64%49%47%55%77%82%83%86%83%80%83%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Santa Monica

In Santa Monica in September, the maximum UV index is 14, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, so it's crucial to take precautions. For the detailed hourly UV index in Santa Monica, you can check here.

Maximum UV Index Levels in Santa Monica for September

The chart shows the monthly maximum UV Index (UVI) for Santa Monica 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 Santa Monica typically reaches 14, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec9111415151414141412108
Data source: Santa Monica 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 Santa Monica Compares to Other Months

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

This table compares monthly weather conditions in Santa Monica, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather12°C (54°F)17 mm (0.7 inches)71%very high
February Weather14°C (58°F)9 mm (0.4 inches)64%extreme
March Weather17°C (63°F)6 mm (0.2 inches)49%extreme
April Weather19°C (66°F)7 mm (0.3 inches)47%extreme
May Weather21°C (70°F)26 mm (1.0 inches)55%extreme
June Weather20°C (69°F)110 mm (4.3 inches)77%extreme
July Weather19°C (66°F)149 mm (5.9 inches)82%extreme
August Weather19°C (67°F)89 mm (3.5 inches)83%extreme
September Weather18°C (64°F)148 mm (5.8 inches)86%extreme
October Weather17°C (62°F)48 mm (1.9 inches)83%extreme
November Weather14°C (58°F)16 mm (0.6 inches)80%very high
December Weather12°C (54°F)12 mm (0.5 inches)83%very high

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