Last updated: February 24, 2025
Experience September in Juneau, where the weather is a captivating blend of contrasts. With maximum temperatures reaching 23°C (74°F), the days can be pleasantly warm, contrasting with cooler averages of 10°C (50°F) and nighttime lows dipping to a chilly -4°C (26°F). The month sees a noteworthy 259 mm (10.2 in) of precipitation spread across 17 days, resulting in a humid atmosphere with levels soaring to an unusual 101%. This unique weather pattern creates a vibrant backdrop for autumnal activities, making September a dynamic time to explore the stunning natural landscapes of Juneau.
As September arrives in Juneau, temperatures start to shift noticeably, signaling the approach of autumn. The average temperature settles at a cool 10°C (50°F), a drop from the warmer summer months, with lows dipping to -4°C (26°F) and daytime highs peaking at a comfortable 23°C (74°F). This transition from the balmy summer temperatures of August reveals a pattern of cooling as the year progresses, with September showcasing a unique blend of lingering warmth and the crispness that autumn brings. Expect the evenings to grow chillier, making it a perfect time for cozy sweaters and enjoying the vibrant fall foliage.
In September, Juneau experiences a striking transition in its weather, with precipitation totaling 259 mm (10.2 in), signaling the tail end of summer's abundance and a precursor to the wetter months ahead. With rainfall spread over 17 days, this month is marked by a noticeable increase from July and August, reflecting a shift in the maritime climate. Following the sector of late summer, September's rainfall prepares the landscape for the impending autumn, as the city's precipitation rises sharply into October, which sees nearly 332 mm (13.1 in). This upward trend in precipitation not only showcases Juneau's lush environment but also underscores the region's robust climatic rhythm—a cycle that shapes its breathtaking natural splendor.
In Juneau, United States, September brings a notable continuation of the region's characteristic high humidity, averaging 101%. This month stands just slightly lower than July and August, which peak at 104% and 108%, respectively, showcasing a trend of increasing moisture during the summer months. As the year progresses, humidity levels remain consistently high, particularly in the middle of the year, with June recording a striking 96%. This month-to-month fluctuation emphasizes Juneau's coastal climate, where the air remains saturated even as the seasons change. Following September, humidity begins to taper off but still hovers around the 98% mark in October, illustrating the persistent dampness that defines this lush and vibrant region throughout the year.
In September, Juneau experiences a UV Index of 6, categorizing the exposure as high, with a burn time of approximately 25 minutes. This marks a noticeable decrease from the intense very high levels seen in the summer months of June and July, which registered UV Indexes of 8 and 9, respectively, demanding just 15 minutes of unprotected sun exposure before the risk of burning escalates. As autumn approaches, the UV Index gradually declines, mirroring the diminishing daylight hours and shifting weather patterns. Despite this decrease, it's essential to remain vigilant, as September's level still calls for caution during sunny days. For detailed information on UV trends throughout the year, check out Juneau UV Index.
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In Juneau, the light begins to dance with the arrival of summer, peaking in May with an impressive 235 hours of sunshine, before gradually declining as the year progresses. June still offers a generous 201 hours, while July and August bring a comforting warmth with 198 and 178 hours, respectively. The sun’s retreat becomes evident in September, where 167 hours signal the transition into fall. As we move into the colder months, the stark contrast is palpable, with sunshine plummeting to 45 hours by December. This rhythmic ebb and flow of daylight not only marks the changing seasons but also enriches the vibrant life in Juneau, reminding residents to savor every sunlit moment before the longer nights set in.
In Juneau, the likelihood of sunny weather takes a notable dip as summer transitions to fall. By September, the chance of sun plummets to a mere 8%, marking it as one of the cloudiest months of the year. This decline follows a brief peak in sunniness over the summer months, particularly in June and July, both at 26%. As the region shifts from the brighter days of mid-summer, the vagaries of Alaska's maritime climate dominate, leaving residents and visitors alike to prepare for a typically overcast September. In contrast, earlier months like February and April demonstrate a greater likelihood of sunshine, with chances reaching 36% and 35% respectively, showcasing the seasonal variability inherent in Juneau's weather patterns.
In Juneau, Alaska, the transformation of daylight throughout the year paints a vivid picture of the changing seasons. As winter recedes, January's meager 7 hours of daylight steadily grows, reaching a peak of 18 hours in June. This dramatic increase, particularly notable in the spring and early summer months, fosters a vibrant atmosphere where the landscape comes alive. However, as summer wanes, daylight begins to retreat once more—by September, the sun graces the city with 12 hours of light, signaling the onset of autumn. This ebb and flow of daylight not only influences the natural rhythms of the environment but also evokes a sense of transition among the residents, marking the passage of time in this unique northern locale.
In September, Juneau experiences a gentle revival in wind activity, with average speeds reaching 2.2 m/s (5 mph), a slight increase from the summer lull. This uptick marks a subtle shift from the calmest months of June and July, which boast the least wind at 1.6 m/s (4 mph) and 1.4 m/s (3 mph), respectively. As summer fades, the winds begin to pick up again, foreshadowing the more brisk conditions typical of the fall months. The average wind speed gradually rises to 2.5 m/s (6 mph) by October, suggesting that September serves as a transitional period, gently nudging Juneau back into a breezier season ahead. This gradual resurgence invites both residents and visitors to appreciate the dynamic weather patterns of this picturesque Alaskan city.
The weather in Juneau 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 Juneau and find detailed weather information for every month.
September and January exhibit stark contrasts in weather patterns. In September, temperatures range from a minimum of -4°C (26°F) to a maximum of 23°C (74°F), with an average of 10°C (50°F), accompanied by significant precipitation totaling 259 mm (10.2 in) over 17 days. This month is characterized by high humidity levels of 101%, creating a damp atmosphere. In contrast, January sees much colder temperatures, with a minimum of -25°C (-13°F) and a maximum of 8°C (47°F), resulting in an average temperature of -4°C (25°F). Precipitation is less frequent, at 215 mm (8.4 in) over 16 days, along with lower humidity at 94%. For more detailed information on January weather, visit Juneau weather in January.
September and February in Juneau present two starkly contrasting weather patterns. In September, temperatures range from a chilly -4°C (26°F) at night to a comfortable 23°C (74°F) during the day, with an average of 10°C (50°F). The month sees significant precipitation, totaling 259 mm (10.2 in) over 17 days, accompanied by high humidity levels at 101%. In contrast, February is much colder, with minimum temperatures plummeting to -24°C (-12°F) and a maximum of just 9°C (48°F), resulting in an average temperature of -5°C (23°F). Additionally, February experiences less precipitation, at 182 mm (7.2 in) across 14 days, with humidity at 90%. For a more detailed overview, you can check Juneau weather in February.
September and March present stark contrasts in weather characteristics. September typically enjoys milder temperatures ranging from a low of -4°C (26°F) to a comfortable maximum of 23°C (74°F), with an average of 10°C (50°F). In contrast, March is significantly colder, with temperatures dipping as low as -18°C (0°F) and averaging around -1°C (30°F), peaking at 10°C (51°F). While both months see similar levels of precipitation, with about 17 days of rain, September experiences nearly 259 mm (10.2 in) of rainfall, significantly more than March's 175 mm (6.9 in). Additionally, September's humidity is notably higher at 101%, compared to 92% in March. For more insights, check out Juneau weather in March.
September weather in Juneau tends to be milder, with average temperatures ranging from a chilly 10°C (50°F) to a warmer max of 23°C (74°F). In contrast, April experiences a colder climate, with temperatures ranging from -13°C (9°F) to a maximum of only 12°C (55°F), making it generally feel more frigid. Additionally, September sees higher precipitation levels, averaging 259 mm (10.2 in) over 17 days, compared to April's 163 mm (6.4 in) with the same number of rainy days. The humidity in September is notably higher at 101%, while April maintains a slightly lower humidity level of 92%. For more details, you can check Juneau weather in April.
When comparing the weather of September and May, September tends to be milder with a higher average temperature of 10°C (50°F) compared to May's average of 7°C (45°F). However, both months experience chilly lows, with September's minimum temperature at -4°C (26°F) and May's at -3°C (26°F). September is also significantly wetter, receiving 259 mm (10.2 in) of precipitation over 17 days, in contrast to May's 174 mm (6.9 in) across 18 days. Humidity levels are notably higher in September at 101%, while May sees slightly lower humidity at 90%. For more details, check out Juneau weather in May.
In September, the weather in Juneau features a wider range of temperatures, with a minimum of -4°C (26°F) and a maximum of 23°C (74°F), resulting in a comfortable average of 10°C (50°F). However, the month is quite rainy, receiving 259 mm (10.2 in) of precipitation over 17 days, contributing to a notably high humidity of 101%. Conversely, June offers slightly warmer conditions with temperatures ranging from a minimum of 2°C (36°F) to a maximum of 25°C (77°F), averaging 11°C (53°F). Precipitation levels are lower in June at 189 mm (7.4 in) over 22 days, and humidity stands at 96%. For more detailed information on June weather, visit Juneau weather in June.
In comparing the weather between September and July, September tends to be cooler with temperatures ranging from a minimum of -4°C (26°F) to a maximum of 23°C (74°F), averaging around 10°C (50°F). In contrast, July features milder temperatures, with a minimum of 7°C (45°F) and a maximum of 25°C (77°F), resulting in an average of 13°C (56°F). Precipitation is notably higher in September at 259 mm (10.2 in) over 17 days, while July sees less rainfall at 164 mm (6.5 in) across 18 days. Both months experience high humidity levels, with September at 101% and July slightly higher at 104%. For additional details on the weather patterns, visit Juneau weather in July.
September weather is generally cooler than August, with average temperatures dropping from 13°C (56°F) in August to 10°C (50°F) in September. The maximum temperature in September reaches 23°C (74°F), compared to 27°C (80°F) in August, highlighting the transition to fall. Precipitation levels are slightly lower in September, totaling 259 mm (10.2 in) over 17 days, compared to August's 280 mm (11.0 in) over 20 days. Humidity also decreases in September, from 108% in August to 101%. For more details, you can check Juneau weather in August.
September weather in Juneau is milder, with temperatures ranging from a minimum of -4°C (26°F) to a maximum of 23°C (74°F) and an average of 10°C (50°F). The month sees considerable rainfall, accumulating to 259 mm (10.2 inches) over 17 days, with high humidity levels reaching 101%. In contrast, October brings cooler temperatures, with a minimum of -11°C (13°F) and a maximum of 14°C (57°F), averaging at 4°C (40°F). Precipitation increases to 332 mm (13.1 inches) over 22 days, accompanied by slightly lower humidity at 98%. For a more detailed look at October weather patterns, check out Juneau weather in October.
September and November reflect a notable transition in weather patterns. In September, temperatures range from a minimum of -4°C (26°F) to a maximum of 23°C (74°F), with an average of 10°C (50°F), making it relatively mild. The month sees significant precipitation, measuring 259 mm (10.2 in) over 17 days, along with a high humidity level of 101%. Contrast this with November, where temperatures drop further, with a minimum of -15°C (6°F) and an average of -1°C (31°F), peaking at only 8°C (47°F). Precipitation increases slightly to 267 mm (10.5 in) over 22 days, while humidity remains high at 97%. The shift from September’s mild and wet climate to November’s colder, more overcast conditions is evident, as detailed in the Juneau weather in November.
In comparing the weather between September and December, it's clear that December experiences much colder temperatures. September sees a minimum of -4°C (26°F) with an average of 10°C (50°F) and a maximum of 23°C (74°F), while December has a chilling minimum of -24°C (-10°F) and an average of -2°C (28°F), with a maximum of only 10°C (50°F). Additionally, December has slightly more precipitation at 292 mm (11.5 in) over 22 days, in contrast to September's 259 mm (10.2 in) spread over 17 days. Despite the colder temperatures, December maintains a high humidity level of 96%, while September reaches an even more humid 101%. For more details, visit Juneau weather in December.
As September unfolds in Juneau, the weather begins to shift dramatically from the warmer summer months. With average temperatures dropping significantly, the crisp morning air often gives way to the brisk chill of autumn, making it a time for layering up. Precipitation levels soar, creating a lush, vibrant landscape, though the frequent rain can lead to many damp days. This transition into fall not only impacts the weather but also transforms the scenery, providing a breathtaking canvas of vibrant colors. For those looking to understand the nuances of Juneau's climate, delve deeper into the details at Juneau Climate.