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September Weather in Fort St. John, Canada

Last updated: June 18, 2025

In September, the average temperature in Fort St. John, Canada is a cool 9°C (49°F), with fluctuations ranging from a chilly -8°C (18°F) to a warm 30°C (85°F). This month brings a modest precipitation amount of 46 mm (1.8 in) over about 8 days, contributing to an average humidity of 83%.

September Temperature in Fort St. John

In September in Fort St. John, the average temperature is 9°C (49°F). Maximum temperatures can reach 30°C (85°F), while the minimum can drop as low as -8°C (18°F). Be prepared for a wide range of temperatures when traveling to Fort St. John this September.

September Weather in Fort St. John: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Fort St. John, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Fort St. John, September typically has an average temperature of 9°C (49°F), with highs reaching up to 30°C (85°F) and lows dropping to around -8°C (18°F).
JanFebMarAprMayJunJulAugSepOctNovDec12921355158615949362114
Data source: Temperature data for Fort St. John 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 Fort St. John

In Fort St. John in September, the precipitation amount is 46 mm (1.8 in) over the course of 8 days.

September Precipitation Trends in Fort St. John

The chart displays monthly precipitation patterns in Fort St. John, 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 Fort St. John, September typically receives around 46 mm (1.8 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec262632274181935546415022
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Fort St. John

In Fort St. John in September, humidity is 83%. With an average temperature of 9°C (49°F), this humidity feels like a damp blanket wrapping around you, making outdoor activities uncomfortable for traveling and requiring extra layers to stay warm and dry.

September Average Humidity in Fort St. John

This chart illustrates the average monthly humidity levels in Fort St. John, 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 Fort St. John is approximately 83%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec94%94%89%86%82%80%83%80%83%87%91%95%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Fort St. John

In Fort St. John in September, the maximum UV index reaches 5, which corresponds to a moderate Exposure Category. Under these conditions, the estimated time to burn is approximately 30 minutes. For more details, you can check the Hourly UV Index in Fort St. John.

Maximum UV Index Levels in Fort St. John for September

The chart shows the monthly maximum UV Index (UVI) for Fort St. John 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 Fort St. John typically reaches 5, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec123577775311
Data source: Fort St. John 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 Fort St. John Compares to Other Months

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

This table compares monthly weather conditions in Fort St. John, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-11°C (12°F)26 mm (1.0 inches)94%low
February Weather-13°C (9°F)26 mm (1.0 inches)94%low
March Weather-6°C (22°F)31 mm (1.2 inches)89%moderate
April Weather2°C (35°F)27 mm (1.1 inches)86%moderate
May Weather10°C (51°F)41 mm (1.6 inches)82%high
June Weather15°C (59°F)81 mm (3.2 inches)80%high
July Weather16°C (61°F)93 mm (3.7 inches)83%high
August Weather15°C (59°F)55 mm (2.2 inches)80%high
September Weather9°C (49°F)46 mm (1.8 inches)83%moderate
October Weather2°C (37°F)41 mm (1.6 inches)86%moderate
November Weather-6°C (21°F)50 mm (2.0 inches)91%low
December Weather-10°C (15°F)22 mm (0.9 inches)95%low

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