nomadseason

September Weather in San Francisco, Colombia

Last updated: August 23, 2025

In September, the average temperature in San Francisco, Colombia reaches a pleasant 23°C (75°F). Expect a comfortable range with minimums dipping to 16°C (62°F) and maximums soaring to 35°C (95°F). However, be prepared for some rain, as 147 mm (5.8 in) of precipitation is likely over 16 days. Don’t forget, the air will feel quite humid, with an average humidity of 80%.

September Temperature in San Francisco

In September in San Francisco, the average temperature is 23°C (75°F), with maximums reaching up to 35°C (95°F) and minimums dropping to as low as 16°C (62°F). This pleasant climate makes it an ideal destination for travelers seeking mild weather and outdoor adventures.

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

The chart illustrates September temperature patterns in San Francisco, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Francisco, September typically has an average temperature of 23°C (75°F), with highs reaching up to 35°C (95°F) and lows dropping to around 16°C (62°F).
JanFebMarAprMayJunJulAugSepOctNovDec727473737474757574737273
Data source: Temperature data for San Francisco 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 Francisco

In San Francisco in September, the precipitation amount is 147 mm (5.8 in) spread over 16 days.

September Precipitation Trends in San Francisco

The chart displays monthly precipitation patterns in San Francisco, 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 Francisco, September typically receives around 147 mm (5.8 inches) of precipitation spread over approximately 16 days.
JanFebMarAprMayJunJulAugSepOctNovDec1061012382522511035594147279425146
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in San Francisco

In San Francisco in September, humidity is 80%. With an average temperature of 23°C (75°F), this humidity feels like a warm, enveloping blanket, making outdoor activities a tad sticky but still manageable for those up for a leisurely exploration.

September Average Humidity in San Francisco

This chart illustrates the average monthly humidity levels in San Francisco, 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 Francisco is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec79%77%80%83%88%87%85%80%80%85%87%83%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in San Francisco

In San Francisco 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 San Francisco, you can check here.

Maximum UV Index Levels in San Francisco for September

The chart shows the monthly maximum UV Index (UVI) for San Francisco 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 Francisco typically reaches 14, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec141516171514141514141312
Data source: San Francisco 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 Francisco Compares to Other Months

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

This table compares monthly weather conditions in San Francisco, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather22°C (73°F)105 mm (4.2 inches)78%extreme
February Weather23°C (74°F)101 mm (4.0 inches)77%extreme
March Weather23°C (74°F)238 mm (9.4 inches)80%extreme
April Weather23°C (74°F)252 mm (9.9 inches)83%extreme
May Weather23°C (74°F)251 mm (9.9 inches)87%extreme
June Weather23°C (74°F)103 mm (4.1 inches)87%extreme
July Weather24°C (76°F)55 mm (2.2 inches)85%extreme
August Weather24°C (76°F)94 mm (3.7 inches)80%extreme
September Weather23°C (75°F)147 mm (5.8 inches)80%extreme
October Weather23°C (73°F)279 mm (11.0 inches)85%extreme
November Weather22°C (72°F)425 mm (16.7 inches)87%extreme
December Weather23°C (73°F)146 mm (5.7 inches)83%extreme

Compare San Francisco's Climate with Cities Worldwide