Last updated: April 22, 2025
Experience the climate of St. John's, Canada, this September, where temperatures range from a brisk minimum of 4°C (39°F) to a warm maximum of 24°C (75°F). With an average temperature hovering around 13°C (56°F), the month offers a mild yet vibrant atmosphere. Be prepared for 107 mm (4.2 in) of precipitation spread over 11 days, contributing to the city's lush scenery. With humidity levels reaching an impressive 90%, September provides a unique coastal charm, making it an ideal time to explore the beauty of this historic city.
September in St. John's, Canada, marks a delightful transition from the warmth of summer to the coolness of autumn. With minimum temperatures averaging around 4°C (39°F) and highs reaching a pleasant 24°C (75°F), this month offers a refreshing blend of warmth and crisp air. The average temperature settles at a comfortable 13°C (56°F), inviting residents and visitors alike to enjoy outdoor activities amidst the stunning fall foliage. As the days grow shorter, the mild conditions of September signal the end of summer, creating a perfect backdrop for exploring the charming coastal landscapes and vibrant local culture.
September ushers in a notable shift in St. John's precipitation patterns, characterized by an average of 107 mm (4.2 in) of rain across 11 days. This volume reflects a return to wetter conditions after the drier summer months of July and August, which saw only 100 mm (3.9 in) and 69 mm (2.7 in) of rain, respectively. As autumn approaches, September’s rainfall is slightly higher than in May and June, indicating a trend where precipitation begins to rise again, paving the way for the wetter months ahead. The city’s climate dances between the extremes, but September’s robust rainfall is a reminder of nature's rhythm, setting the stage for the more pronounced precipitation of October and November.
In September, St. John's experiences a marked shift as humidity levels settle at 90%, a slight dip from the summer peak of 94% in July. This trend reflects the gradual transition from the humid heat of summer to the crispness of fall. While September's humidity remains relatively high, it is a part of a general decline that begins in August, showcasing how the city subtly prepares for the cooler months ahead. As autumn approaches, the air retains a lingering moisture, making it a unique experience for residents and visitors alike.
In September, St. John's experiences a UV Index of 7, categorizing it as high, with a burn time of just 25 minutes. This indicates that while the summer sun begins to wane, the risk of skin damage remains significant. The UV Index trends over the year reveal a marked increase from the lows of winter, where January and February show minimal exposure, to the highs of summer, peaking in June and July. As autumn approaches, the UV levels start their gradual decline, but September still demands caution, reminding residents and visitors alike of the lingering effects of UV rays as they enjoy the last warm days of the season. For more detailed insights, visit St. John's UV Index.
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As summer fades, September in St. John's, Canada offers a stunning transition with 251 hours of sunshine—a significant drop from August's peak of 306 hours, yet still a remarkable month for light. The trend of increasing daylight from the depths of winter peaks mid-year, illustrating a vibrant summer that gradually fades into the cooler fall months. With sunshine hours diminishing from a high of 286 in July, September remains a month where the warmth lingers, encouraging outdoor adventures and stunning twilight views. This seasonal shift not only marks the beginning of autumn but continues to celebrate the beauty of St. John's, with weeks filled with golden hues and crisp air, making it an ideal time for exploration before the long winter sets in.
In St. John's, Canada, September brings a noticeable shift in the weather, as the likelihood of sunny days rises to 38%—the highest point since March. This increase indicates a transition from the cooler summer months, where sunshine chances were relatively stable around 25-33%. Compared to earlier months, September offers a promising opportunity for outdoor activities, as it embraces the tail end of summer with the potential for more sun-filled skies. Following September, however, the chance of sun declines sharply as the crisp, colder months approach, making those sunny September days even more precious for residents and visitors alike.
As September unfolds in St. John's, Canada, daylight begins to wane after the vibrant summer months. This transition sees daylight drop to an average of 12 hours, a noticeable reduction from the 14 hours experienced in August. The trend throughout the year highlights a gradual increase in daylight from the depths of winter in January, where the sun graces the city for only 8 hours, peaking in the lush summer months of June to August with 15 hours of golden light. As autumn approaches, the diminishing daylight signals a shift in the seasons, leading toward the long evenings of October and November. This rhythmic ebb and flow of daylight encapsulates the unique charm of Newfoundland's landscape, where each season brings its own distinct character.
As September rolls into St. John's, Canada, the average wind speed dips slightly to 5.1 m/s (12 mph), reflecting a gentle transition from the brisk summer breezes of August. This trend of diminishing wind speeds becomes particularly noticeable in the warmer months, with July experiencing the calmest winds at 4.7 m/s (11 mph). However, as the days shorten and autumn approaches, wind speeds begin to pick up again in October, climbing back to 5.9 m/s (13 mph). This pattern illustrates a seasonal rhythm, where the lighter winds of late summer gradually give way to crisper gusts, heralding the arrival of fall. Overall, September serves as a pivotal point in this annual cycle, balancing the lingering warmth of summer with the fresh promise of the upcoming season.
The weather in St. John's 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 St. John's and find detailed weather information for every month.
September and January present strikingly different weather conditions. In September, temperatures range from a minimum of 4°C (39°F) to a pleasant maximum of 24°C (75°F), with an average of 13°C (56°F). This month experiences substantial rainfall, totaling 107 mm (4.2 in) over about 11 days, alongside high humidity levels of 90%. In contrast, January is characterized by colder temperatures, with lows dipping to -14°C (7°F) and a maximum of only 12°C (54°F), averaging around -2°C (29°F). January also sees a similar amount of precipitation at 113 mm (4.5 in) but spreads across 13 days and features a lower humidity of 83%. For more detailed insights into the conditions of January, you can explore St. John's weather in January.
September and February present starkly contrasting weather conditions. In September, temperatures range from a mild 4°C (39°F) at night to a warm 24°C (75°F) during the day, with an average of 13°C (56°F). This month tends to be quite humid at 90%, with 107 mm (4.2 in) of precipitation occurring over 11 days. In contrast, February experiences much colder temperatures, plunging to a low of -16°C (3°F) and reaching a maximum of just 10°C (50°F), averaging -3°C (26°F). Despite slightly less precipitation at 102 mm (4.0 in) over 12 days, February boasts a lower humidity level of 84%. For a more detailed look at February's climate, you can check out St. John's weather in February.
September and March present contrasting weather conditions. In September, temperatures range from a mild 4°C (39°F) at night to a comfortable maximum of 24°C (75°F) during the day, accompanied by an average temperature of 13°C (56°F). The month sees considerable precipitation of 107 mm (4.2 in) over 11 days, and humidity levels are quite high at 90%. In stark contrast, March is significantly colder, with temperatures dipping as low as -14°C (8°F) at night and only reaching up to 13°C (55°F) during the day, averaging -2°C (29°F). The total precipitation for March is slightly lower at 100 mm (3.9 in), spread over 13 days, and humidity is a bit lower at 85%. For more details on the weather patterns in March, check out St. John's weather in March.
In comparing September and April weather, September offers a milder temperature range with a minimum of 4°C (39°F) and an average of 13°C (56°F), reaching a maximum of 24°C (75°F). In contrast, April experiences cooler temperatures, starting at a minimum of -6°C (22°F) and averaging just 2°C (36°F), with a maximum of 15°C (60°F). Precipitation levels are somewhat similar, with September receiving 107 mm (4.2 in) over 11 days and April slightly less at 103 mm (4.0 in) over 14 days. Both months exhibit high humidity, with September at 90% and April at 88%. For a more detailed look at April’s weather specifics, check out St. John's weather in April.
In comparing the weather of September and May, September tends to be warmer, with average temperatures ranging from a minimum of 4°C (39°F) to a maximum of 24°C (75°F). In contrast, May experiences cooler temperatures, with a minimum of -3°C (27°F) and an average high of only 20°C (68°F). While September sees more significant warmth overall, it also brings higher precipitation levels, averaging 107 mm (4.2 in) over 11 days, compared to May's 80 mm (3.1 in) over 12 days. Interestingly, both months maintain high humidity levels at around 90%. For a closer look at May's climate, you can check St. John's weather in May.
September weather shows a gradual transition towards cooler temperatures, with minimums of 4°C (39°F) and an average of 13°C (56°F), while June maintains a slightly lower average of 10°C (51°F) but shares the same maximum of 24°C (75°F). Precipitation is more pronounced in September, totaling 107 mm (4.2 in) over 11 days, compared to June's 86 mm (3.4 in) across 12 days. Humidity levels remain high in both months, with September at 90% and June at 91%. For a detailed look at June's conditions, visit St. John's weather in June.
In comparing the weather of September and July, we see distinct differences and similarities. September generally experiences slightly cooler temperatures, with a minimum of 4°C (39°F) and an average of 13°C (56°F), compared to July, which has a minimum of 6°C (43°F) and an average of 15°C (58°F). July records a maximum temperature of 25°C (76°F), just one degree warmer than September's high of 24°C (75°F). Precipitation levels are quite similar, with September experiencing slightly more rain at 107 mm (4.2 in) over 11 days, while July receives 100 mm (3.9 in) across 10 days. Humidity is also higher in September at 90%, compared to 94% in July. For more detailed information, you can visit St. John's weather in July.
In comparing the weather of September to that of August, it is clear that September tends to be cooler and wetter. While August enjoys a milder temperature range with a minimum of 8°C (46°F) and an average of 17°C (62°F), September sees temperatures drop to a minimum of 4°C (39°F) and an average of 13°C (56°F). Additionally, September experiences more precipitation, measuring 107 mm (4.2 in) over 11 days, compared to August's 69 mm (2.7 in) over 10 days. The humidity remains relatively high in both months, with September at 90% and August slightly higher at 93%. For more details on August's weather, you can check St. John's weather in August.
September and October exhibit notable differences in weather patterns. In September, temperatures range from a minimum of 4°C (39°F) to a maximum of 24°C (75°F), averaging around 13°C (56°F), while October sees cooler temperatures, dropping to a minimum of 0°C (32°F) and averaging only 8°C (48°F), with a maximum of 22°C (72°F). Precipitation is slightly lower in October at 97 mm (3.8 in) compared to September's 107 mm (4.2 in), although the number of rainy days increases to 12 days in October, compared to 11 in September. Humidity also decreases slightly from September’s 90% to October's 87%, indicating a shift towards drier conditions. For more details on October's weather, check St. John's weather in October.
In September, temperatures range from a minimum of 4°C (39°F) to a maximum of 24°C (75°F), with an average of 13°C (56°F). The month experiences a high level of precipitation, totaling 107 mm (4.2 in) over 11 days and maintaining a humidity level of 90%. In contrast, November sees a significant drop in temperature, with minimums plummeting to -6°C (22°F) and an average of just 4°C (40°F), while maximums reach up to 16°C (62°F). Precipitation levels remain similar, at 108 mm (4.3 in) over 13 days, but the humidity decreases to 84%. For those interested in specifics, check out St. John's weather in November for more details.
September weather in St. John's displays a mild transition from summer to fall, with temperatures ranging from a minimum of 4°C (39°F) to a maximum of 24°C (75°F), and an average of 13°C (56°F). The month sees considerable rainfall, totaling 107 mm (4.2 in) over 11 days, coupled with high humidity levels reaching 90%. In contrast, December experiences a significant drop in temperatures, with minimums plunging to -10°C (15°F) and an average of 0°C (33°F). Precipitation is slightly higher at 133 mm (5.3 in), occurring over 16 days, while humidity decreases to 83%. This stark shift highlights the transition from the relatively mild, damp weather of September to the cold, snowy conditions typical of December. For more details, you can check St. John's weather in December.
As September rolls in, St. John's experiences a notable shift in its weather, bidding farewell to the warmth of summer while welcoming the crispness of fall. With increased humidity and a steady chance of rainfall over more than a third of the month, this transition period can feel quite moist and cool compared to the preceding summer months. Daily temperatures begin to cool down, with the average dropping to 13°C, while the likelihood of encountering a rainy day rises significantly. This creates a unique blend of vibrant autumn colors and the occasional lingering warmth, making September a distinctive time in St. John's weather calendar. For more detailed insights into what to expect throughout the year, check out St. John's Climate.