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September Weather in Monterey, United States

Last updated: June 24, 2025

In September, the average temperature in Monterey, United States is a pleasant 22°C (72°F). Visitors can expect temperatures to range from a cool 7°C (45°F) to a warm 35°C (96°F). Precipitation is also a factor to consider, with approximately 119 mm (4.7 in) of rain falling over 10 days. The average humidity hovers around 71%, adding a touch of tropical warmth to this charming destination.

September Temperature in Monterey

In September in Monterey, the average temperature is 22°C (72°F). The maximum can reach 35°C (96°F), and the minimum can be as low as 7°C (45°F). It's an ideal time for travelers to enjoy a variety of outdoor activities while being prepared for both warm and cooler temperatures.

September Weather in Monterey: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Monterey, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Monterey, September typically has an average temperature of 22°C (72°F), with highs reaching up to 35°C (96°F) and lows dropping to around 7°C (45°F).
JanFebMarAprMayJunJulAugSepOctNovDec394551586874787672624744
Data source: Temperature data for Monterey 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 Monterey

In Monterey in September, the total precipitation amount is 119 mm (4.7 in) over the span of 10 days.

September Precipitation Trends in Monterey

The chart displays monthly precipitation patterns in Monterey, 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 Monterey, September typically receives around 119 mm (4.7 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec10819316115313813313313011913278150
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Monterey

In Monterey in September humidity is 71%. With an average temperature of 22°C (72°F), this humidity feels like the air is thick and slightly stifling, making outdoor activities require frequent breaks to stay hydrated and cool.

September Average Humidity in Monterey

This chart illustrates the average monthly humidity levels in Monterey, 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 Monterey is approximately 71%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%86%86%82%83%83%80%74%71%78%88%88%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Monterey

In Monterey in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Monterey.

Maximum UV Index Levels in Monterey for September

The chart shows the monthly maximum UV Index (UVI) for Monterey 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 Monterey typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec36710111111109753
Data source: Monterey 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 Monterey Compares to Other Months

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

This table compares monthly weather conditions in Monterey, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather4°C (40°F)108 mm (4.3 inches)87%moderate
February Weather7°C (45°F)192 mm (7.6 inches)86%high
March Weather11°C (51°F)161 mm (6.3 inches)86%high
April Weather14°C (58°F)153 mm (6.0 inches)82%very high
May Weather20°C (68°F)138 mm (5.4 inches)82%extreme
June Weather23°C (74°F)133 mm (5.2 inches)83%extreme
July Weather25°C (78°F)133 mm (5.2 inches)80%extreme
August Weather24°C (76°F)130 mm (5.1 inches)74%very high
September Weather22°C (72°F)119 mm (4.7 inches)71%very high
October Weather17°C (62°F)132 mm (5.2 inches)78%high
November Weather9°C (48°F)78 mm (3.1 inches)88%moderate
December Weather7°C (44°F)150 mm (5.9 inches)88%moderate

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