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September Weather in San Francisco, Nicaragua

Last updated: August 31, 2025

In September, the average temperature in San Francisco, Nicaragua reaches a warm 28°C (82°F). Expect a cozy minimum of 23°C (74°F) and occasional peaks up to 35°C (95°F). This month also brings about 341 mm (13.4 in) of precipitation over 27 days, contributing to an average humidity of 77%. Stay prepared for both the warmth and the wet!

September Temperature in San Francisco

In September, in San Francisco, the average temperature is 28°C (82°F). Maximums can reach 35°C (95°F), and minimums can be as low as 23°C (74°F). This makes San Francisco a warm and pleasant destination for travelers looking to enjoy a sunny getaway.

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 28°C (82°F), with highs reaching up to 35°C (95°F) and lows dropping to around 23°C (74°F).
JanFebMarAprMayJunJulAugSepOctNovDec858687868483858382818385
Data source: Temperature data for San Francisco 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 San Francisco

In San Francisco in September, the precipitation amount is 341 mm (13.4 in) spread over 27 days, indicating a relatively wet period.

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 341 mm (13.4 inches) of precipitation spread over approximately 27 days.
JanFebMarAprMayJunJulAugSepOctNovDec446352573611252983414171036
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in San Francisco

In San Francisco in September humidity is 77%. With an average temperature of 28°C (82°F), this humidity feels like a warm, enveloping blanket that can make outdoor activities sticky and exhausting, but also offers a lush vibrancy to the landscape, perfect for enjoying leisurely strolls in the early morning or late afternoon.

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 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec63%62%59%59%59%68%78%79%77%77%75%67%
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 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 San Francisco.

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 13, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec11121414141413131313109
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 Weather29°C (85°F)4 mm (0.2 inches)63%extreme
February Weather30°C (86°F)4 mm (0.2 inches)62%extreme
March Weather30°C (87°F)6 mm (0.2 inches)59%extreme
April Weather30°C (86°F)35 mm (1.4 inches)59%extreme
May Weather29°C (84°F)257 mm (10.1 inches)59%extreme
June Weather28°C (83°F)361 mm (14.2 inches)68%extreme
July Weather30°C (85°F)125 mm (4.9 inches)77%extreme
August Weather29°C (84°F)298 mm (11.7 inches)79%extreme
September Weather28°C (82°F)341 mm (13.4 inches)77%extreme
October Weather27°C (82°F)417 mm (16.4 inches)77%extreme
November Weather28°C (83°F)103 mm (4.1 inches)75%very high
December Weather29°C (85°F)6 mm (0.2 inches)66%very high

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