Last updated: February 24, 2025
Explore the enchanting September weather in Bar Harbor, United States, where the transition from summer to fall brings a delightful climate to this coastal gem. Daytime temperatures reach a maximum of 27°C (81°F), with an average of 16°C (61°F), offering a pleasant backdrop for outdoor adventures. As the sun sets, temperatures can dip to a minimum of 5°C (42°F), highlighting the crispness of early autumn. While visitors can expect about 95 mm (3.7 in) of precipitation over 7 days, the humidity rests comfortably at 77%, creating a refreshing atmosphere. Whether you're wandering along the shoreline or exploring the charming town, September in Bar Harbor promises a captivating experience infused with natural beauty and vibrant hues.
As summer gently fades into autumn, September in Bar Harbor ushers in a delightful shift in temperatures. With a minimum of 5°C (42°F) and an average reaching 16°C (61°F), visitors can bask in the milder days before the chill of winter sets in. The maximum temperature peaks at a comfortable 27°C (81°F), making it an ideal time for outdoor adventures amidst the stunning fall foliage. This transitional month serves as a bridge from the warmth of August, where highs averaged around 29°C (85°F), while providing a pleasant respite from the inevitable drop in temperatures that follows in October. As nature transforms, September offers a unique blend of warmth and crispness, inviting exploration and appreciation of Bar Harbor’s breathtaking landscapes.
In September, Bar Harbor experiences a moderate precipitation total of 95 mm (3.7 in), reflecting a slight uptick compared to the drier summer months. With only 7 days of rainfall, this is one of the drier months of the year, suggesting a transition as the region shifts from the warmer summer season. The precipitation trend aligns with the overall pattern of increased moisture towards late summer and autumn, laying the groundwork for the wetter months ahead, particularly October and November. As we move into September, residents and visitors can enjoy the lingering warmth, while also being mindful of the potential for rain as nature prepares for the changing seasons.
In September, Bar Harbor experiences a slight uptick in humidity, with levels reaching 77%. This marks an increase from the drier summer months of June through August, which maintain a consistent 74% humidity. As the seasons transition toward autumn, the atmosphere begins to reclaim some moisture, hinting at the upcoming changes in weather. Interestingly, the higher humidity levels in September precede a return to more humid conditions in October, which sees humidity levels rise to 82%. Overall, the trend showcases the gradual shift from the summer's relative dryness to the crisp, refreshing air of fall, making September a period of notable atmospheric transition in Bar Harbor.
As September arrives in Bar Harbor, the UV Index settles at 7, placing it in the high exposure category. This marks a slight decline from the summer peak, where values reached 9 and 10, indicative of very high exposure. With a burn time extending to 25 minutes, sun protection becomes paramount, especially as outdoor activities might still be popular during this transitional month. Compared to earlier in the year, such as the UV Index of 2 in January, this indicates a significant increase in sun intensity. Embrace the beautiful fall days, but be mindful of the sun's strength, especially as the season shifts. For more detailed insights, visit Bar Harbor UV Index.
UV Risk Categories
As summer fades, September in Bar Harbor offers a delightful blend of warmth and crispness, boasting 281 hours of sunshine. This month stands out as a transition period, where the sun still shines brightly, though slightly less than in the peak of summer, which sees up to 326 hours in August. The gradual decline in sunshine hours mirrors the shift in seasons; however, September still provides more sunlight than the winter months, making it an ideal time for exploring the stunning coastal landscapes and vibrant fall foliage. With temperatures still lingering from the summer heat, visitors can revel in the outdoor activities and breathtaking scenery, all while experiencing the tail end of summer's golden glow. The trend of increasing sunshine from winter to summer peaks beautifully here, reminding us that while the days may shorten, the beauty of Bar Harbor continues to shine.
In Bar Harbor, September enjoys a 39% chance of sunny weather, which aligns closely with the sunny probabilities seen in mid-summer months like June and August. As autumn approaches, the likelihood of clear skies remains relatively steady, suggesting that those looking to bask in sunny days before the winter chill can find some joy in September. While not the sunniest month, this percentage reflects a notable recovery from the drier July, which dips to 25%. Interestingly, the sunny weather trends pick up again in October, hinting that September serves as a pleasant bridge from summer to fall, perfect for outdoor explorations amidst the stunning scenery.
As summer gracefully gives way to fall in Bar Harbor, September marks a transitional month in daylight duration. With 12 hours of sunlight, the days begin to shorten as the region shifts from the long, sun-drenched days of June and July, which boast 15 hours of daylight each. The gradual decline from a vibrant summer into the milder autumn sees a reduction in daylight by one hour from August, when the days begin to wane. This trend continues into October, where daylight decreases further to 10 hours. The cyclical rhythm of the seasons is evident, inviting both locals and visitors to savor the lingering warmth of early autumn while preparing for the cozy, shorter days of winter ahead.
As summer transitions to fall, September in Bar Harbor greets visitors with a gentle caress of wind, averaging 3.7 m/s (8 mph). This slight rise from the calm breezes of August signifies a shift in the season, yet it remains one of the calmer months compared to the earlier parts of the year. As autumn sets in, the wind begins to pick up slightly, hinting at the brisk conditions to come in October and November, which see average speeds rise to around 3.8 m/s and 4.3 m/s, respectively. This subtle upturn in wind speed, from the peaceful summer lulls to the refreshing breezes of early fall, creates an invigorating atmosphere that perfectly complements the stunning foliage and the retreating summer warmth, inviting residents and tourists alike to embrace the seasonal changes in this coastal haven.
The weather in Bar Harbor 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 Bar Harbor and find detailed weather information for every month.
September and January present starkly contrasting weather conditions. In September, temperatures range from a cool minimum of 5°C (42°F) to a pleasant maximum of 27°C (81°F), with an average of 16°C (61°F). The month also brings about 95 mm (3.7 in) of precipitation over 7 days, combined with a humidity level of 77%. In contrast, January experiences much colder temperatures, plunging to a minimum of -23°C (-8°F) and only reaching a maximum of 11°C (51°F), with an average of -4°C (25°F). Precipitation is slightly higher at 98 mm (3.9 in) spread across 9 days, and the humidity rises to 88%. For more specifics on January weather, you can check out Bar Harbor weather in January.
In comparing the weather of September and February, it's evident that these months present stark contrasts. September enjoys a mild atmosphere with average temperatures around 16°C (61°F) and a maximum reaching 27°C (81°F), while February is characterized by much colder conditions, with average temperatures hovering around -3°C (26°F) and a maximum of just 13°C (56°F). Precipitation levels are relatively similar, with September receiving 95 mm over 7 days and February 90 mm over 10 days, though February's higher humidity at 88% compared to September's 77% adds a chill to the air. For a closer look at what to expect, check out Bar Harbor weather in February.
In comparing the weather of September and March, we see a stark contrast in temperatures and conditions. September typically enjoys a much warmer climate with daily averages around 16°C (61°F), peaking at a comfortable 27°C (81°F), while March experiences significantly colder temperatures, averaging 0°C (32°F) and dipping as low as -18°C (0°F). Precipitation levels are relatively close, with September receiving 95 mm (3.7 in) over about 7 days compared to March's 73 mm (2.9 in) across 9 days. Additionally, March has higher humidity at 85%, compared to September's 77%, contributing to a chillier atmosphere. For more detailed insights, you can visit Bar Harbor weather in March.
When comparing the weather in September and April, several notable differences arise. September enjoys a milder climate with average temperatures around 16°C (61°F), ranging from a minimum of 5°C (42°F) to a maximum of 27°C (81°F), while April experiences cooler temperatures with an average of 6°C (43°F), dipping to a minimum of -4°C (24°F) and reaching a maximum of 18°C (65°F). In terms of precipitation, April sees more rainfall, totaling 129 mm (5.1 in) over 13 days, compared to September's 95 mm (3.7 in) over just 7 days. Additionally, humidity levels are slightly higher in April at 81%, compared to September's 77%. For a detailed look at the weather specifics, check out Bar Harbor weather in April.
September and May offer distinct weather experiences, showcasing the transition between seasons. In September, temperatures range from a minimum of 5°C (42°F) to a maximum of 27°C (81°F), with an average of 16°C (61°F). The month sees about 95 mm (3.7 in) of precipitation over approximately 7 days, accompanied by a humidity level of 77%. In contrast, May presents cooler temperatures, with a minimum of 2°C (36°F) and a maximum of 25°C (78°F), averaging 11°C (52°F). Precipitation is slightly lower at 92 mm (3.6 in) but occurs over more days, totaling around 11. Both months are relatively humid, with May at 76%. For more detailed insights into May weather, check out Bar Harbor weather in May.
In comparing the weather between September and June, both months exhibit similar average temperatures, with June showing a slightly higher maximum temperature of 30°C (86°F) compared to September’s maximum of 27°C (81°F). September tends to be a bit wetter, with 95 mm (3.7 in) of precipitation over 7 days, while June sees 79 mm (3.1 in) over 9 days, indicating a more consistent chance of rain in June. Humidity levels are also comparable, with September averaging 77% and June at 74%. For a closer look at what to expect, check out Bar Harbor weather in June.
When comparing the weather in September and July, notable differences emerge. September experiences cooler temperatures, with a minimum of 5°C (42°F) and an average of 16°C (61°F), while July is warmer, starting at a minimum of 11°C (53°F) and averaging 19°C (67°F). The maximum temperature in July reaches 30°C (86°F), slightly higher than September's maximum of 27°C (81°F). Additionally, September tends to be wetter, with 95 mm (3.7 in) of precipitation over 7 days, compared to July's 80 mm (3.2 in) over 10 days. Humidity levels are also slightly higher in September at 77%, compared to July's 74%. For more details on July weather, check out Bar Harbor weather in July.
In comparison to August, September experiences cooler temperatures, with a minimum of 5°C (42°F) and an average of 16°C (61°F), compared to August's minimum of 12°C (53°F) and average of 20°C (68°F). While both months see a fair amount of precipitation, September is wetter, receiving 95 mm (3.7 in) over 7 days, whereas August has 73 mm (2.9 in) over 8 days. Additionally, September's humidity increases slightly to 77%, compared to 74% in August. For more detailed information about August weather, visit Bar Harbor weather in August.
September tends to be warmer than October, with average temperatures ranging from a minimum of 5°C (42°F) to a maximum of 27°C (81°F). In contrast, October sees cooler temperatures, with lows dropping to 0°C (32°F) and a maximum of 21°C (70°F). While both months experience significant rainfall, October is wetter with 107 mm (4.2 in) of precipitation over 11 days compared to September's 95 mm (3.7 in) over 7 days. Additionally, October has slightly higher humidity levels at 82%, compared to September's 77%. For more insights, you can check out Bar Harbor weather in October.
September and November showcase a stark contrast in weather conditions. In September, temperatures range from a mild minimum of 5°C (42°F) to a pleasant maximum of 27°C (81°F), with an average of 16°C (61°F). The month experiences a total precipitation of 95 mm (3.7 in) over about 7 days, accompanied by a relative humidity of 77%. In contrast, November brings significantly colder temperatures, with a minimum of -15°C (6°F), an average of just 4°C (40°F), and a maximum of 17°C (63°F). Precipitation also increases to 130 mm (5.1 in), occurring over 12 days and further contributing to the higher humidity of 85%. For a closer look at what to expect, check out Bar Harbor weather in November.
In September, weather tends to be warm and mild, with temperatures ranging from a minimum of 5°C (42°F) to a maximum of 27°C (81°F) and an average temperature of 16°C (61°F). Humidity is at a comfortable 77%, accompanied by some rainfall totaling 95 mm (3.7 in) over about 7 days. In contrast, December ushers in much colder conditions, with temperatures plunging to a minimum of -22°C (-7°F) and an average of -1°C (30°F), while the maximum reaches only 15°C (59°F). The month is also wetter, with 138 mm (5.4 in) of precipitation over 11 days and humidity increasing to 84%. For more details on December weather, you can visit Bar Harbor weather in December.
As September rolls into Bar Harbor, the warmth of summer begins to fade, but temperatures remain pleasantly mild, averaging 16°C (61°F), contrasting with the cooler months ahead. This transitional month often boasts more variable weather, with occasional spikes of warmth reaching up to 27°C (81°F) and brisk evenings hinting at autumn's approach, as temperatures can dip to 5°C (42°F). Despite the inviting warmth, September typically experiences increased precipitation, averaging 95 mm (3.7 in) over about seven days, which contributes to a notable humidity level of 77%. For those looking to explore Bar Harbor during this time, the mix of lingering summer warmth and the crispness of impending fall creates a uniquely charming atmosphere. To learn more about what to expect throughout the year, visit Bar Harbor Climate.