nomadseason

September Weather in San Diego, Mexico

Last updated: August 27, 2025

In September, the average temperature in San Diego, Mexico hovers around 28°C (83°F). Expect a minimum of 19°C (67°F) and potential highs reaching 41°C (105°F). With 167 mm (6.6 in) of precipitation spread across 19 days, the air remains notably humid, averaging at 84%.

September Temperature in San Diego

In September in San Diego, the average temperature is 28°C (83°F). Maximums can reach 41°C (105°F), while minimums can drop as low as 19°C (67°F). Be prepared for warm weather and stay hydrated during your travels!

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

The chart illustrates September temperature patterns in San Diego, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Diego, September typically has an average temperature of 28°C (83°F), with highs reaching up to 41°C (105°F) and lows dropping to around 19°C (67°F).
JanFebMarAprMayJunJulAugSepOctNovDec677075818584848582797268
Data source: Temperature data for San Diego generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in San Diego

In San Diego in September, the precipitation amount is 167 mm (6.6 in) over a span of 19 days.

September Precipitation Trends in San Diego

The chart displays monthly precipitation patterns in San Diego, 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 Diego, September typically receives around 167 mm (6.6 inches) of precipitation spread over approximately 19 days.
JanFebMarAprMayJunJulAugSepOctNovDec573141561061531141161672346326
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in San Diego

In San Diego in September, humidity is 84%. With an average temperature of 28°C (83°F), this humidity feels like a thick blanket enveloping you, making every step feel heavier and the air almost stifling for traveling.

September Average Humidity in San Diego

This chart illustrates the average monthly humidity levels in San Diego, 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 Diego is approximately 84%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%86%83%80%82%79%72%74%84%92%91%91%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in San Diego

In San Diego 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 Diego.

Maximum UV Index Levels in San Diego for September

The chart shows the monthly maximum UV Index (UVI) for San Diego 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 Diego typically reaches 12, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec710121212131312121187
Data source: San Diego 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 Diego Compares to Other Months

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

This table compares monthly weather conditions in San Diego, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather19°C (67°F)57 mm (2.3 inches)88%high
February Weather21°C (70°F)31 mm (1.2 inches)86%very high
March Weather24°C (75°F)41 mm (1.6 inches)83%extreme
April Weather27°C (81°F)56 mm (2.2 inches)80%extreme
May Weather29°C (85°F)106 mm (4.2 inches)82%extreme
June Weather29°C (84°F)153 mm (6.0 inches)79%extreme
July Weather29°C (84°F)114 mm (4.5 inches)72%extreme
August Weather29°C (85°F)116 mm (4.6 inches)74%extreme
September Weather28°C (83°F)167 mm (6.6 inches)84%extreme
October Weather26°C (79°F)234 mm (9.2 inches)92%extreme
November Weather22°C (73°F)62 mm (2.5 inches)91%very high
December Weather20°C (69°F)26 mm (1.0 inches)91%high

Compare San Diego's Climate with Cities Worldwide