nomadseason

September Weather in Fairfield, United States

Last updated: June 24, 2025

In September, the average temperature in Fairfield, United States is a pleasant 23°C (74°F). Temperatures can vary significantly, with a minimum of 7°C (45°F) and a maximum reaching up to 36°C (97°F). During this month, you can expect about 83 mm (3.3 in) of precipitation over approximately 6 days, contributing to an average humidity level of 59%.

September Temperature in Fairfield

In September in Fairfield, the average temperature is 23°C (74°F). Maximum temperatures can reach 36°C (97°F), while minimums can drop as low as 7°C (45°F). This range makes it essential for travelers to pack both light clothing for the warm days and warmer layers for the cooler evenings.

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

The chart illustrates September temperature patterns in Fairfield, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Fairfield, September typically has an average temperature of 23°C (74°F), with highs reaching up to 36°C (97°F) and lows dropping to around 7°C (45°F).
JanFebMarAprMayJunJulAugSepOctNovDec394152586876797774614944
Data source: Temperature data for Fairfield 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 Fairfield

In Fairfield in September, the precipitation amount is 83 mm (3.3 in) over the course of 6 days.

September Precipitation Trends in Fairfield

The chart displays monthly precipitation patterns in Fairfield, 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 Fairfield, September typically receives around 83 mm (3.3 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec9111714416921093111148831698389
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Fairfield

In Fairfield in September humidity is 59%. With an average temperature of 23°C (74°F), this humidity feels like a warm, inviting embrace, making it comfortable for traveling as long as you stay hydrated and take breaks in the shade.

September Average Humidity in Fairfield

This chart illustrates the average monthly humidity levels in Fairfield, 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 Fairfield is approximately 59%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%79%77%78%82%81%75%61%59%69%82%88%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Fairfield

In Fairfield 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 Fairfield.

Maximum UV Index Levels in Fairfield for September

The chart shows the monthly maximum UV Index (UVI) for Fairfield 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 Fairfield typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec46710111111109754
Data source: Fairfield 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 Fairfield Compares to Other Months

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

This table compares monthly weather conditions in Fairfield, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather4°C (39°F)91 mm (3.6 inches)82%moderate
February Weather5°C (42°F)116 mm (4.6 inches)79%high
March Weather11°C (53°F)144 mm (5.7 inches)77%high
April Weather14°C (58°F)169 mm (6.7 inches)78%very high
May Weather20°C (68°F)210 mm (8.3 inches)82%extreme
June Weather24°C (76°F)93 mm (3.6 inches)81%extreme
July Weather26°C (80°F)111 mm (4.4 inches)75%extreme
August Weather25°C (78°F)148 mm (5.8 inches)61%very high
September Weather23°C (74°F)83 mm (3.3 inches)59%very high
October Weather16°C (61°F)169 mm (6.7 inches)69%high
November Weather9°C (49°F)83 mm (3.3 inches)82%moderate
December Weather7°C (44°F)89 mm (3.5 inches)87%moderate

Compare Fairfield's Climate with Cities Worldwide