September Weather in Banff, Canada

Last updated: April 22, 2025

In September, Banff, Canada, experiences a striking range of temperatures, with highs reaching a pleasant 26°C (79°F) and lows dipping to a brisk -10°C (15°F). The month averages around 5°C (42°F), providing a crisp backdrop for outdoor adventures. While the picturesque landscapes may entice visitors, they should be prepared for 66 mm (2.6 in) of precipitation spread over 11 days, contributing to a 79% humidity level. This combination of climate conditions makes September a unique time to explore Banff's breathtaking natural beauty, where the changing seasons offer both vibrant foliage and the serene tranquility of early fall.

September Temperature in Banff

In September, Banff, Canada, experiences a noticeable transition as summer slowly gives way to autumn. With minimum temperatures averaging around -10°C (15°F) and maximums reaching a pleasant 26°C (79°F), it's a time when outdoor enthusiasts can still enjoy the stunning landscapes without the summer crowds. The average temperature settles at 5°C (42°F), offering a refreshing coolness that invites long hikes and explorations amidst the vibrant fall foliage. This month stands out as a bridge to the chilly months ahead, with temperatures gradually dropping as the year progresses, contrasting sharply with the winter extremes that follow in October. Overall, September’s mild conditions make it an appealing month for both adventure and scenic beauty in the heart of the Rockies.

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

The chart illustrates September temperature patterns in Banff, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec851725374653524226166
Data source: Temperature data for Banff 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 Banff

In September, Banff experiences a transition into autumn, characterized by a moderate precipitation amount of 66 mm (2.6 in), falling on about 11 days of the month. This marks a slight decrease compared to the summer months, where June peaked with 115 mm. As the vibrant greens of summer fade, the rainfall in September helps prepare the landscape for the stunning fall foliage that follows. The gradual decline in both precipitation volume and rainy days suggests a shift toward drier conditions, setting the stage for the crisp and cooler weather of October. Overall, September's precipitation serves as a gentle reminder of nature's cycle while still offering plenty of opportunities for outdoor adventures amid the beautiful changing scenery.

September Precipitation Trends in Banff

The chart displays monthly precipitation patterns in Banff, 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.
JanFebMarAprMayJunJulAugSepOctNovDec1942526975115857667544946
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Banff

As the summer fades into autumn, September in Banff, Canada, welcomes a subtle shift in humidity levels, dipping to 79%. This marks a gradual decline from the more humid summer months, where humidity hovered around 80% and above. The transition from high summer humidity, seen in July and August, begins to pave the way for the cooler and drier air of fall. Notably, this trend of decreased humidity continues into October, suggesting a seasonal shift towards the crispness of early winter. With each passing month, there’s a refreshing sense of change in the air, preparing the stunning landscapes of Banff for the vibrant autumn foliage to come.

September Average Humidity in Banff

This chart illustrates the average monthly humidity levels in Banff, with September's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how September's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec95%95%92%89%86%84%84%80%79%88%94%97%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Banff

As summer fades into autumn, September in Banff sees a UV Index of 7, categorizing exposure as high with a burn time of 25 minutes. This marks a slight decline from the peak summer months, where the index reached 9, indicating very high levels of UV radiation. Nevertheless, outdoor enthusiasts should remain vigilant, as the sun can still pose a risk. With the transition into fall, it's crucial to balance enjoying the stunning landscapes of this national park while taking appropriate sun safety measures. For further details on UV Index trends throughout the year, visit Banff UV Index.

Maximum UV Index Levels in Banff for September

The chart shows the monthly maximum UV Index (UVI) for Banff 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.
JanFebMarAprMayJunJulAugSepOctNovDec235799987421
Data source: Banff 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.

September Sunshine in Banff

As summer wanes and autumn approaches, September in Banff, Canada, offers a splendid transition marked by 263 hours of sunshine. While this is a noticeable decrease from the peak of 381 hours in July, it still boasts a vibrant glow compared to the colder months ahead. The month seamlessly bridges the radiant summer’s end and the crisp fall days, reflecting a significant drop from summer highs yet remaining considerably brighter than the winter months, where sunlight dips to as low as 134 hours in January. This pattern of diminishing daylight captures the enchanting essence of September, inviting nature lovers and adventure seekers to relish the stunning landscapes in a softer, golden light, before winter blankets the region.

Monthly Sunshine Duration in Banff: September Highlighted

The September sunshine duration represents the total number of hours Banff experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec134h177h253h285h316h338h381h332h263h220h153h158h
Data source: Banff September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Banff During September

As September ushers in the transition to autumn, Banff, Canada, enjoys a notable likelihood of sunny weather, with a 45% chance of sunshine during the month. This percentage reflects a slight dip from the summer peak in July, which stands at 53%, but remains significantly higher than the early months of the year, with January and February recording just 36% and 26% respectively. The trend indicates that while September may herald the approach of cooler days, it still offers a delightful opportunity for outdoor enthusiasts to bask in the lingering warmth of summer. With a balance of sunny spells and hints of fall foliage, it’s an enchanting time to explore the breathtaking landscapes of this Canadian gem.

Percentage of Sunny Days in September in Banff

The chart illustrates the percentage of sunny days in Banff throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Banff experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec36%26%42%48%35%47%53%40%45%48%24%23%
Data source: Banff September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Banff in September

As summer gives way to autumn, September in Banff witnesses a gentle decline in daylight duration, with an average of 12 hours. Following the peak of 16 hours in June, the daylight starts to taper off as nature prepares for the colder months ahead. While still abundant, September’s sunlight is a reminder of the transition, offering a balance of warm days and crisp evenings. This gradual decrease leads into October, where daylight decreases further to 10 hours, mirroring the rhythm of the seasons and inviting visitors to enjoy the stunning fall foliage before winter’s arrival. The shifting light invites a serene exploration of Banff's breathtaking landscapes, perfect for embracing the changing seasons.

Average Daylight Hours in Banff for September

The chart illustrates the variation in daylight duration in Banff throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec8h 27m10h 1m11h 56m13h 54m15h 36m16h 28m15h 59m14h 27m12h 33m10h 36m8h 52m7h 57m
Data source: Banff daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Banff

As September rolls into Banff, Canada, the winds pick up a refreshing momentum, with an average speed of 2.4 m/s (5 mph), marking a notable increase from the summer months. This invigorating breeze is a delightful contrast to the calmer air experienced in July and August, where winds slowed to their annual lows. Interestingly, as the seasons transition from the warmth of summer to the crispness of autumn, wind speeds generally trend upward, hinting at the impending changes nature has in store. With October following closely behind at 2.1 m/s (5 mph), it seems the winds are gearing up for a brisk autumn, creating an enchanting atmosphere for visitors amidst Banff’s stunning fall foliage.

Average September Wind Speed in Banff

The chart displays monthly wind speed patterns in Banff, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec2.42.02.32.01.81.91.71.92.4 m/s2.12.62.1
Data source: Banff September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Banff Compares to Other Months

The weather in Banff changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Banff and find detailed weather information for every month.

In September, Banff experiences milder temperatures, with a minimum of -10°C (15°F) and an average of 5°C (42°F), peaking at a pleasant 26°C (79°F). The month sees about 66 mm (2.6 in) of precipitation spread over 11 days, paired with a humidity level of 79%. In contrast, January's weather is much harsher, as temperatures plunge to a minimum of -38°C (-36°F) and average around -13°C (8°F), with a maximum of just 2°C (36°F). The precipitation drops significantly to 19 mm (0.8 in) over only 5 days, but humidity rises to a high 95%. For more detailed insights, you can view Banff weather in January.

September and February present stark contrasts in weather conditions. In September, temperatures range from a brisk -10°C (15°F) at night to a warm 26°C (79°F) during the day, with an average of 5°C (42°F). This month brings about 66 mm (2.6 in) of precipitation over approximately 11 days, accompanied by a humidity level of 79%.

In contrast, February is marked by much colder temperatures, dipping down to a frigid -37°C (-34°F) at night and only reaching up to 4°C (40°F) during the day, with an average temperature of -15°C (5°F). Precipitation is lower, at 42 mm (1.6 in) across the same 11 days, but the humidity is notably higher at 94%.

For more detailed weather information, you can visit Banff weather in February.

September and March present stark contrasts in weather. September offers a much milder climate, with temperatures ranging from a chilly minimum of -10°C (15°F) to a warm maximum of 26°C (79°F), coupled with an average of 5°C (42°F). In September, there's a higher chance of pleasant days, experiencing 66 mm (2.6 in) of precipitation over 11 days and a relatively comfortable humidity of 79%. In contrast, March is notably colder, with temperatures plummeting as low as -33°C (-27°F) and only reaching a maximum of 11°C (51°F), averaging -8°C (18°F). While March sees less precipitation at 52 mm (2.1 in), it spans 12 days, accompanied by higher humidity at 92%. To learn more about the specifics of March weather conditions, you can check Banff weather in March.

In comparing the weather of September and April, we observe notable differences in temperature and overall conditions. September offers a wider temperature range with a minimum of -10°C (15°F), an average of 5°C (42°F), and a maximum of 26°C (79°F), making it relatively mild compared to April. In contrast, April experiences lower temperatures, ranging from a minimum of -23°C (-9°F) to a maximum of 14°C (57°F), with an average temperature of -4°C (25°F). Precipitation is fairly similar in both months, with September receiving 66 mm (2.6 in) over 11 days and April showing slightly higher precipitation of 69 mm (2.7 in) over 13 days. Additionally, April has higher humidity levels at 89% compared to September's 79%. For more specific details on April conditions, you can visit Banff weather in April.

In September, temperatures range from a chilly -10°C (15°F) at night to a warm 26°C (79°F) during the day, with an average of 5°C (42°F). The month sees about 66 mm (2.6 in) of precipitation over 11 days and a humidity level of 79%. In contrast, May features cooler temperatures, with a minimum of -15°C (5°F) and a maximum of 19°C (67°F), averaging around 3°C (37°F). Rainfall is slightly higher in May at 75 mm (3.0 in) over 14 days, and humidity increases to 86%. For more details on May weather, you can check Banff weather in May.

In comparing the weather of September and June, we see notable differences in temperature and precipitation. September experiences a broader temperature range, with minimums dipping to -10°C (15°F) and maximums reaching up to 26°C (79°F), while June's temperatures are generally milder, ranging from -6°C (21°F) at night to 31°C (88°F) during the day. Furthermore, June tends to be wetter, receiving 115 mm (4.5 in) of precipitation over 17 days compared to September's 66 mm (2.6 in) over 11 days. Both months exhibit high humidity levels, with June slightly higher at 84% versus September's 79%. For a more detailed look at the weather in June, you can visit Banff weather in June.

In comparing September to July, we see notable differences in temperature and precipitation. September has a wider temperature range, with minimums reaching -10°C (15°F) and maximums hitting 26°C (79°F), averaging around 5°C (42°F). This contrasts with July, which sees milder minimums of -1°C (30°F) and maximums soaring up to 32°C (89°F), averaging 12°C (53°F). Additionally, July experiences higher precipitation levels, with 85 mm (3.4 in) over 15 days, compared to September's 66 mm (2.6 in) across 11 days. Humidity remains relatively high in both months, at 79% in September and slightly higher at 84% in July. For a more detailed look at conditions during July, check out Banff weather in July.

In comparing the weather between September and August, September experiences a wider temperature range, with minimum temperatures dropping to -10°C (15°F) and maximums reaching 26°C (79°F). In contrast, August sees milder conditions, with minimums at -4°C (25°F) and maximums peaking at 28°C (82°F). While precipitation is slightly lower in September at 66 mm (2.6 in) over 11 days, August receives 76 mm (3.0 in) across 12 days, accompanied by a marginally higher humidity level of 80% compared to September’s 79%. For more detailed information, check out the Banff weather in August.

In comparing the weather between September and October, there is a notable shift towards colder temperatures. September features a temperature range that stretches from a minimum of -10°C (15°F) to a pleasant maximum of 26°C (79°F), with an average of around 5°C (42°F). However, as October arrives, temperatures plummet, with a minimum of -31°C (-24°F) and an average of -3°C (27°F), although it still reaches a maximum of 18°C (65°F). Precipitation decreases slightly from 66 mm (2.6 in) over 11 days in September to 54 mm (2.1 in) across 10 days in October, but humidity rises from 79% to 88%. For more details on October's weather, you can check Banff weather in October.

In September, temperatures range from a minimum of -10°C (15°F) to a maximum of 26°C (79°F), with an average of 5°C (42°F). The month experiences relatively moderate precipitation of 66 mm (2.6 in) over 11 days, alongside a humidity level of 79%. In contrast, November brings a significant drop in temperatures, with a minimum of -30°C (-22°F), an average of -9°C (17°F), and a maximum of only 6°C (44°F). Precipitation decreases slightly to 49 mm (1.9 in) over the same number of days, but humidity rises to 94%, making the air feel much colder. For more details on November weather, you can check Banff weather in November.

In September, the weather in Banff is characterized by moderate temperatures, with a minimum of -10°C (15°F), an average of 5°C (42°F), and a maximum reaching up to 26°C (79°F). This month sees relatively more precipitation, with 66 mm (2.6 in) distributed over 11 days, resulting in a humidity level of 79%. In contrast, December brings much colder conditions, with temperatures plummeting to a minimum of -37°C (-34°F) and an average of -14°C (7°F), while the maximum temperature barely reaches 3°C (38°F). Precipitation decreases slightly to 46 mm (1.8 in) over 9 days, but humidity rises significantly to 97%, creating a brisk and frosty atmosphere. For more detailed information about the conditions in the winter season, check out Banff weather in December.

Compare Banff's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Banff

As summer gracefully gives way to autumn, September in Banff brings a unique and varied climate that stands out from both the balmy days of July and the crisp chill of October. Daytime temperatures can still reach a warm 26°C, creating a beautiful contrast with the cooler average of 5°C and the potential for colder nights plummeting to -10°C. With humidity levels around 79% and about 11 days of precipitation, this month often showcases a stunning interplay of sunshine and rain, painting the landscape in vibrant fall colors. If you're planning a visit, consider how September’s weather offers a distinct blend of summer warmth and the early hints of winter, making it an enticing time to explore the beauty of Banff. For more detailed information, check out the link: Banff Climate.