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September Weather in Arroyo Grande, Mexico

Last updated: August 26, 2025

In September, the average temperature in Arroyo Grande, Mexico is a warm 26°C (78°F), with temperatures ranging from a comfortable 19°C (67°F) to a sweltering 34°C (94°F). Expect significant precipitation, with about 227 mm (8.9 in) falling over 23 days, and the air will likely feel quite humid, with an average humidity of 85%.

September Temperature in Arroyo Grande

In September in Arroyo Grande, the average temperature is 26°C (78°F). The maximum can reach 34°C (94°F), while the minimum can drop as low as 19°C (67°F). This pleasant climate makes it an ideal time for travelers to explore and enjoy outdoor activities in Arroyo Grande.

September Weather in Arroyo Grande: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Arroyo Grande, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Arroyo Grande, September typically has an average temperature of 26°C (78°F), with highs reaching up to 34°C (94°F) and lows dropping to around 19°C (67°F).
JanFebMarAprMayJunJulAugSepOctNovDec757781828481797978787774
Data source: Temperature data for Arroyo Grande 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 Arroyo Grande

In Arroyo Grande in September, the precipitation amount is 227 mm (8.9 in) over the course of 23 days.

September Precipitation Trends in Arroyo Grande

The chart displays monthly precipitation patterns in Arroyo Grande, 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 Arroyo Grande, September typically receives around 227 mm (8.9 inches) of precipitation spread over approximately 23 days.
JanFebMarAprMayJunJulAugSepOctNovDec442132172178231227146355
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Arroyo Grande

In Arroyo Grande in September, humidity is 85%. With an average temperature of 26°C (78°F), this humidity feels like a heavy blanket enveloping you, making every step feel laborious and sweat trickling down your back, which can be quite challenging for traveling.

September Average Humidity in Arroyo Grande

This chart illustrates the average monthly humidity levels in Arroyo Grande, 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 Arroyo Grande is approximately 85%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec70%64%54%61%75%83%83%85%85%79%76%75%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Arroyo Grande

In Arroyo Grande 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 Arroyo Grande.

Maximum UV Index Levels in Arroyo Grande for September

The chart shows the monthly maximum UV Index (UVI) for Arroyo Grande 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 Arroyo Grande typically reaches 13, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec911131314141413131188
Data source: Arroyo Grande 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 Arroyo Grande Compares to Other Months

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

This table compares monthly weather conditions in Arroyo Grande, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather24°C (75°F)4 mm (0.2 inches)70%very high
February Weather25°C (77°F)4 mm (0.2 inches)64%extreme
March Weather27°C (81°F)2 mm (0.1 inches)54%extreme
April Weather28°C (83°F)1 mm (0.0 inches)61%extreme
May Weather29°C (84°F)31 mm (1.2 inches)75%extreme
June Weather27°C (81°F)172 mm (6.8 inches)83%extreme
July Weather26°C (80°F)177 mm (7.0 inches)83%extreme
August Weather26°C (79°F)231 mm (9.1 inches)85%extreme
September Weather26°C (78°F)227 mm (8.9 inches)85%extreme
October Weather26°C (78°F)146 mm (5.8 inches)79%extreme
November Weather25°C (77°F)35 mm (1.4 inches)76%very high
December Weather24°C (75°F)5 mm (0.2 inches)74%very high

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