Last updated: April 22, 2025
In September, Cornwall, Canada experiences a delightful transition as summer gradually gives way to autumn. The maximum temperature can reach a warm 27°C (82°F), while the average hovers around a comfortable 16°C (61°F), allowing for pleasant outdoor activities. However, the temperature can dip to a cool 3°C (38°F) at times. This month also sees a significant precipitation total of 96 mm (3.8 in) across about 10 days, contributing to the region's lush landscape. With humidity levels averaging 85%, the air feels rich and vibrant, encapsulating the essence of early fall in this picturesque Canadian locale.
As summer wanes, September in Cornwall, Canada ushers in a refreshing change with temperatures that balance the warmth of summer and the coolness of autumn. The month kicks off with a comfortable average temperature of 16°C (61°F), offering ideal conditions for outdoor activities. Daytime highs can reach a pleasant 27°C (82°F), inviting locals and visitors alike to explore the stunning landscapes before the chill of fall sets in. Evenings start to feel crisp, with lows dipping to around 3°C (38°F), reminding everyone that winter is just around the corner. This transitional month showcases a beautiful shift in weather, making it a delightful time to appreciate Cornwall's natural beauty and vibrant community as they prepare for the colder months ahead.
In September, Cornwall experiences a notable uptick in precipitation, with an average of 96 mm (3.8 in), making it one of the wetter months of the year, alongside November. This increase contrasts with the summer's relatively drier conditions, where July and August recorded only 68 mm and 73 mm respectively. With 10 days of precipitation, September strikes a balance, signaling the transition into the fall season. The trend suggests that as the year progresses toward winter, rainfall tends to intensify, laying the groundwork for the 135 mm of precipitation expected in November. Overall, September's weather encapsulates a shift in the climate pattern, blending the lingering warmth of summer with the impending chill of autumn, urging residents to prepare for the wetter months ahead.
As summer gives way to autumn, September in Cornwall, Canada, experiences a slight dip in humidity, settling at 85%. This is a characteristic trend as the month transitions from the muggy conditions of August, which peaks at a notable 87% humidity. Throughout the year, Cornwall maintains a consistently high humidity range, primarily hovering between 82% and 87%, with the summer months often seeing the highest levels. Notably, the humidity during September reflects the gradual moderation of the season, hinting at the approach of cooler temperatures while still retaining a palpable moisture in the air. This persistent humidity, experienced across the months, contributes to Cornwall's lush landscapes and vibrant ecosystems, making it a unique destination year-round.
September in Cornwall, Canada, marks a transition as summer days begin to wane, with the UV Index settling at a moderate-to-high level of 7. This aligns with a consistent trend from the previous months, where the UV Index peaked during the height of summer before tapering off slightly. With a burn time of just 25 minutes, residents and visitors alike should take caution and prioritize sun protection, reflecting the high exposure category typical for this time of year. As the seasons shift, let’s stay informed and protect our skin from harmful rays—learn more at Cornwall UV Index.
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September in Cornwall, Canada, brings a stunning farewell to summer with 271 hours of sunshine, making it the perfect time to enjoy outdoor activities before the chill of autumn sets in. Following the sun-drenched months of July and August, which boast impressive totals of 341 and 351 hours respectively, September still holds on to a generous amount of light, significantly outpacing the dreariness of the colder months ahead. This gradual decline in sunshine hours is a reminder of the seasonal shift, as daylight wanes in October to 220 hours. Embrace the vibrant colors of fall, knowing you'll still bask in plenty of warm rays before winter descends.
In September, Cornwall experiences a promising chance of sunny weather, with a likelihood of 41% sunshine gracing the skies. This marks a continuation of a trend observed during the late summer months, where August peaks at 44%, providing a warm and sunny backdrop for outdoor activities. Interestingly, this slight dip in September's sunny potential is consistent with the transitional shift into autumn, as temperatures begin to cool. Overall, while September might not match the summer's sunshine intensity, it still offers a delightful blend of sun interspersed with the first hints of fall.
As September unfolds in Cornwall, Canada, daylight begins its gentle retreat from the long, sun-drenched days of summer. With approximately 12 hours of daylight, September marks a transition from the peak brightness of July and August, where daylight extended to 15 hours. This month signifies a subtle shift towards autumn, echoing the rhythms of nature as the days gradually shorten, reminiscent of the 11 hours of sunshine experienced in March. Following the warm embrace of summer, Cornish residents savor the lingering light, a fleeting reminder of the vibrant seasons soon to come, before falling to the 10 hours of October. Embracing the changing light serves as a poignant reminder of the cyclical beauty of the year.
As September winds sweep through Cornwall, Canada, they bring with them a refreshing shift in atmosphere, with an average wind speed of 5.5 m/s (12 mph). This gentle breeze is a pleasant transition from the lighter winds of July and August, where speeds dipped to 4.7 m/s (11 mph) and 4.6 m/s (10 mph), respectively. Interestingly, September's winds begin to hint at the approaching autumn, a trend that is further solidified as speeds increase again in October to 4.5 m/s (10 mph). Notably, the average wind speed for September aligns closely with the slightly higher speeds of earlier spring months, such as April and May, emphasizing a balance between the lingering warmth of summer and the subtle embrace of fall. As the year progresses, the winds will reach their peak in winter months, but for now, September offers a delightful mix of gentle movement that stirs the air and refreshes the spirit.
The weather in Cornwall 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 Cornwall and find detailed weather information for every month.
September and January present stark contrasts in weather conditions. In September, temperatures range from a mild 3°C (38°F) at night to a warm average of 16°C (61°F), peaking at 27°C (82°F) during the day. The month sees about 96 mm (3.8 in) of rainfall over approximately 10 days, accompanied by high humidity levels at 85%. In contrast, January experiences a frigid climate, with temperatures dipping as low as -20°C (-3°F) and an average of -5°C (23°F), reaching a maximum of only 14°C (58°F). Precipitation is slightly lower at 81 mm (3.2 in) over the same number of days, while humidity remains similar at 84%. The dramatic shift from September’s warmth to January’s cold highlights the seasonal extremes typical in many regions. For a closer look at January’s weather, refer to Cornwall weather in January.
September and February present stark contrasts in weather patterns. In September, temperatures range from a minimum of 3°C (38°F) to a pleasant maximum of 27°C (82°F), with an average of 16°C (61°F). Despite experiencing about 96 mm (3.8 in) of precipitation over approximately 10 days, the humidity remains high at 85%, contributing to a generally warm and humid atmosphere. In stark contrast, February sees much colder conditions, with temperatures dipping as low as -20°C (-4°F) and averaging -5°C (22°F). The maximum temperature reaches only 9°C (49°F), and while precipitation is slightly lower at 93 mm (3.7 in), it spans over about 12 days, accompanied by a similar humidity level of 84%. For more details on February weather, you can learn more here.
September and March present stark contrasts in weather patterns. In September, the temperatures are generally mild, ranging from a minimum of 3°C (38°F) to an average of 16°C (61°F), with highs reaching 27°C (82°F). This month experiences roughly 96 mm (3.8 in) of precipitation over about 10 days, paired with a relatively high humidity of 85%. Conversely, March is much colder, featuring temperatures that dip as low as -19°C (-2°F) and average around -2°C (28°F), with a maximum of just 11°C (53°F). Precipitation in March totals 75 mm (2.9 in) across 13 days, and humidity levels remain high at 86%. For a closer look at what to expect during March, you can check out Cornwall weather in March.
September and April present contrasting weather conditions. In September, temperatures range from a mild 3°C (38°F) to a warm 27°C (82°F), with an average of 16°C (61°F), making it a more comfortable month overall. The humidity is relatively high at 85%, and while there is some precipitation, totaling 96 mm (3.8 in) over about 10 days, it generally feels more pleasant.
In comparison, April experiences much cooler temperatures, varying from a chilly -8°C (18°F) to a moderate 18°C (65°F), averaging only 4°C (39°F). This month sees slightly less precipitation, 85 mm (3.4 in), but it occurs over 12 days, leading to a damp feeling with a humidity of 86%. Overall, September is much warmer and drier compared to the brisk and wetter conditions of April. For more insights on April weather, you can refer to Cornwall weather in April.
In comparing the weather of September and May, it's clear that September tends to be warmer overall, with average temperatures reaching 16°C (61°F) compared to May's average of just 9°C (49°F). September experiences higher maximum temperatures as well, peaking at 27°C (82°F) versus May’s 24°C (76°F). Both months see similar humidity levels at 85%, but September has slightly more precipitation, with 96 mm (3.8 in) over 10 days compared to May's 88 mm (3.5 in) spread across 13 days. For more detailed insights into May weather, you can visit Cornwall weather in May.
When comparing the weather in September and June, we notice several notable differences despite similarities. In September, temperatures range from a chilly minimum of 3°C (38°F) to a pleasant maximum of 27°C (82°F), with an average temperature of 16°C (61°F). The humidity is relatively high at 85%, and there are about 10 days of precipitation, totaling 96 mm (3.8 in). Conversely, June tends to have slightly warmer temperatures, with a minimum of 0°C (33°F) and a maximum of 29°C (84°F), averaging around 15°C (60°F). While June also sees a comparable precipitation total of 97 mm (3.8 in), it experiences a bit more rainfall spread over 12 days, accompanied by a slightly lower humidity level of 82%. For more details on June weather, visit Cornwall weather in June.
When comparing the weather in September and July, it’s clear that September experiences cooler temperatures, with a minimum of 3°C and an average of 16°C, while July boasts milder conditions, with a minimum of 11°C and an average of 20°C. July also enjoys warmer maxima, reaching up to 30°C compared to September’s maximum of 27°C. Additionally, while both months have ten days of precipitation, September tends to be wetter overall, with 96 mm of rain compared to July's 68 mm. Interestingly, humidity levels are quite similar, at 85% for September and 86% for July. For more information on July weather specifics, check out Cornwall weather in July.
September weather presents a notable shift compared to August. While September boasts a cooler average temperature of 16°C (61°F) with a maximum of 27°C (82°F), August enjoys warmer temperatures, averaging 20°C (68°F) and reaching highs of 30°C (86°F). Precipitation levels in September are higher at 96 mm (3.8 in) over 10 days, compared to August's 73 mm (2.9 in) with the same number of rainy days. Additionally, while September's humidity is slightly lower at 85%, August maintains a higher humidity level at 87%. For more details on August weather, you can visit Cornwall weather in August.
In September, temperatures range from a minimum of 3°C (38°F) to a maximum of 27°C (82°F), with an average of 16°C (61°F). The month sees about 96 mm (3.8 in) of rainfall over 10 days, accompanied by relatively high humidity at 85%. In contrast, October experiences cooler weather, with temperatures dipping to a minimum of -2°C (29°F) and averaging 10°C (50°F), peaking at 24°C (75°F). Precipitation slightly decreases to 77 mm (3.0 in) across 11 days, while humidity remains consistent at 85%. For a closer look at what to expect, check out Cornwall weather in October.
September and November exhibit strikingly different weather patterns. In September, temperatures range from a mild 3°C (38°F) to a warm 27°C (82°F), with an average of 16°C (61°F). The month sees about 96 mm (3.8 in) of precipitation over approximately 10 days, accompanied by a high humidity level of 85%. In contrast, November experiences much cooler temperatures, ranging from a minimum of -12°C (10°F) to a maximum of 20°C (68°F), with an average of just 4°C (39°F). Precipitation increases to 135 mm (5.3 in) over 15 days, maintaining the same humidity level of 85%. For more details on November weather specifically, check out Cornwall weather in November.
September and December exhibit starkly contrasting weather patterns. In September, temperatures range from a mild 16°C (61°F) on average, peaking at a warm 27°C (82°F), with only moderate rainfall of 96 mm (3.8 in) spread over approximately 10 days and high humidity at 85%. In sharp contrast, December sees much colder conditions, with an average temperature of -2°C (29°F) and frigid lows dipping down to -19°C (-3°F). Although the precipitation is comparable at 97 mm (3.8 in), it occurs over a slightly longer period of 13 days, and the humidity remains relatively lower at 84%. For more detailed information about December weather, visit Cornwall weather in December.
As the summer wraps up, September in Cornwall brings a refreshing transition marked by milder temperatures and an increase in humidity. While the mercury can still reach highs that evoke the lingering warmth of summer, the cooler evenings remind us that autumn is on the horizon. With an average of 85% humidity and about 10 days of precipitation, it's a month where occasional showers can add a cozy touch to the landscape, making it perfect for enjoying the vibrant fall foliage. For a deeper understanding of how Cornwall's September weather compares to other months, be sure to check out Cornwall Climate.