Last updated: August 21, 2025
In September, the charming region of Nagano, Japan, experiences a dynamic climate characterized by a maximum temperature reaching 32°C (89°F) and an average of 19°C (67°F), providing a warm backdrop for early autumn activities. Visitors can expect refreshing cool nights with a minimum of 7°C (44°F). However, this period is also marked by significant rainfall, with 194 mm (7.6 in) of precipitation spread across 19 days, resulting in a high humidity level of 89%. This combination of warmth and moisture makes September a vibrant yet variable month, perfect for exploring the breathtaking landscapes of Nagano.
September in Nagano, Japan, marks a delightful transition into autumn, with temperatures exhibiting a gentle decline from the warmth of summer. The month opens with a comfortable average temperature of 19°C (67°F), providing a pleasant backdrop for outdoor activities and the stunning fall foliage. As temperatures dip, the minimum temperature settles at 7°C (44°F), while the pleasant high can reach up to 32°C (89°F), showcasing the last remnants of summer's heat. Overall, the shift in climate not only brings a refreshing coolness but also invites locals and visitors alike to embrace the natural beauty and vibrant atmosphere that characterizes this enchanting time of year.
In September, Nagano experiences a notable shift in its weather pattern as the summer rains begin to taper off, yet precipitation remains robust at 194 mm (7.6 in) spread over 19 days. This marks a slight decrease from August's heavier rainfall of 198 mm (7.8 in) but still reflects the region's characteristic monsoon influence. As the month progresses, the refreshing showers help sustain the lush landscapes while hinting at the forthcoming autumn transition. With an average precipitation level that is higher than many other months, September continues the trend of significant moisture, as seen in July's peak and June's abundant rainfall, setting the stage for the crisp, cooler days of October ahead.
In September, Nagano experiences a slight dip in humidity, with levels around 89%, providing a subtle transition from the peak summer moisture. This month stands out as the humidity gradually shifts from the balmy heights of 92% in July and August, revealing a typical trend as summer wanes into autumn. While the air remains relatively humid, particularly compared to the chilly winter months ahead, September offers a glimpse of relief, setting the stage for the cooler, crisper days of October. Overall, the humidity levels in Nagano reflect a cyclical pattern, with the highest percentages nestled in the summer months, followed by a gradual decrease as the seasons change.
September in Nagano, Japan, ushers in a very high UV Index of 10, with a burn time of just 15 minutes. This marks a slight decrease from the extreme levels experienced during the summer months, yet caution is still essential when soaking up the sun. Notably, as the season transitions from August's peak, awareness of UV exposure remains crucial for outdoor activities. While September signals the start of autumn, the UV levels remain significantly elevated compared to the earlier months of the year, reflecting an overall trend of increasing intensity from spring into summer. For those planning outdoor adventures, understanding the UV index is vital; check here for more information: Nagano UV Index.
UV Risk Categories
As September unfolds in Nagano, Japan, the region enjoys a delightful 243 hours of sunshine, a radiant close to summer that hints at the coming autumn. Following the warm embrace of August, which basked in a generous 290 hours of sunlight, September's glow remains inviting, even as days begin to shorten. The trend of increasing sunlight from early spring through summer peaks in May, with a remarkable 300 hours, before gently tapering off. This subtle transition signals the end of the vibrant summer while still offering pleasant, sunlit days for outdoor exploration. As Nagano prepares to welcome the cooler temperatures of fall, September serves as a beautiful bridge, blending sunlight and crisp air, making it an ideal time to appreciate the region's natural beauty.
In Nagano, Japan, September offers a moderate chance of sunny weather, sitting at 25%, which aligns closely with several summer months. The likelihood of sunshine slightly dips from the vibrant summer months of July and August, both of which feature a 31% and 22% chance respectively. However, as autumn approaches, sunny days become a bit more common again in October, rising to 35%. This trend suggests that while September may not boast the sunniest days, it serves as a transitional period where the warm summer hues gradually give way to the crisp, colorful embrace of autumn. Visitors can expect a mix of pleasant weather, making it a delightful time to explore Nagano’s natural beauty.
As September unfolds in Nagano, Japan, the days begin to subtly shorten, offering around 12 hours of daylight. This marked transition follows the peak summer months, where the sun graced the region with up to 14 hours of bright daylight in June, July, and August. While September retains a generous amount of light, it signals the onset of autumn, gently diminishing from the summer's abundance. The pattern of daylight duration in this vibrant city showcases a beautiful ebb and flow throughout the year, with rapidly lengthening days in spring, peaking in summer, and gradually retreating as winter approaches, creating an ever-changing canvas of natural light.
As the seasons transition in Nagano, Japan, September brings a gentle breeze, with an average wind speed of 1.6 m/s (4 mph). This slight uptick from the slower summer months reflects the gradual shift towards autumn, where the winds begin to weave through the vibrant colors of changing foliage. Compared to the 1.3 m/s in July and 1.5 m/s in August, September’s breezes offer a breath of fresh air, inviting residents and visitors alike to enjoy the outdoors. This moderate wind speed continues into October and November, maintaining a consistent and refreshing atmosphere, while a mild decrease in wind during the summer months hints at the tranquil beauty of Nagano’s seasonal cycle.
Weather in Nagano varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Nagano, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present starkly contrasting weather conditions. In September, temperatures range from a mild 7°C (44°F) at night to a warm 32°C (89°F) during the day, with an average of 19°C (67°F). The month is characterized by high humidity at 89% and considerable precipitation, totaling 194 mm (7.6 in) over 19 days. In contrast, January plunges into the depths of winter, with temperatures dipping as low as -15°C (6°F) and averaging around -2°C (29°F). While January is slightly drier with 144 mm (5.7 in) of precipitation over 21 days, it maintains a similarly high humidity level at 88%. For more information on the specific weather patterns during this chilly month, you can check out Nagano weather in January.
September and February present starkly contrasting weather conditions. In September, the temperatures fluctuate from a mild 7°C (44°F) at night to a warm average of 19°C (67°F), peaking at a hot 32°C (89°F) during the day. This month also experiences significant rainfall, totaling 194 mm (7.6 in) over 19 days, accompanied by high humidity at 89%. In contrast, February is characterized by much colder weather, with temperatures ranging from a frigid -14°C (7°F) overnight to a maximum of 16°C (61°F) during the day, resulting in an average of -1°C (30°F). Precipitation levels are lower at 129 mm (5.1 in), also spread across 19 days, with slightly lower humidity at 86%. For more detailed insights, you can visit Nagano weather in February.
September and March present quite contrasting weather patterns. In September, temperatures range from a mild minimum of 7°C (44°F) to a warm maximum of 32°C (89°F), with an average of 19°C (67°F). This month also experiences significant rainfall, with 194 mm (7.6 in) over 19 days and high humidity at 89%. In contrast, March is much cooler, with temperatures ranging from a frigid minimum of -9°C (16°F) to a maximum of 21°C (70°F), averaging just 4°C (39°F). The precipitation in March is lower at 133 mm (5.2 in) over 18 days, and the humidity is noticeably lower at 81%. For more detailed insights, you can visit Nagano weather in March.
September and April present notably different weather conditions. In September, temperatures range from a mild 19°C (67°F) to a warm maximum of 32°C (89°F), making it feel quite summery, while April's temperatures are cooler, with a minimum of -5°C (22°F) and an average of only 9°C (48°F). Additionally, September sees a higher level of precipitation with 194 mm (7.6 in) falling over 19 days, in contrast to April's 141 mm (5.5 in) over 16 days. The humidity is also higher in September at 89%, compared to April's 78%. For more detailed information on weather specifics in April, you can check Nagano weather in April.
In comparing the weather between September and May, we find notable differences in temperature and humidity. September experiences a wider temperature range, with a minimum of 7°C (44°F) and a maximum of 32°C (89°F), resulting in an average of 19°C (67°F). In contrast, May starts cooler, with a minimum of 0°C (33°F) and an average temperature of 15°C (59°F), although it also reaches a similar high of 31°C (88°F). Precipitation is higher in September, totaling 194 mm (7.6 in) over 19 days, compared to May's 160 mm (6.3 in) over 16 days. Additionally, the humidity is notably higher in September at 89%, while May presents a more moderate level at 81%. For more details, you can refer to Nagano weather in May.
In comparing the weather between September and June, we find that both months experience moderate temperatures and substantial humidity. September sees a minimum temperature of 7°C (44°F) and can peak at 32°C (89°F), which is slightly warmer than June's range of 5°C (41°F) to a maximum of 30°C (87°F). Precipitation is notably high in both months, with September receiving 194 mm (7.6 in) over 19 days, while June has a total of 171 mm (6.7 in) across 18 days. Overall, September tends to be a bit warmer and wetter than June. For more detailed insights, you can check Nagano weather in June.
When comparing the weather in September and July, distinct differences emerge. September typically offers cooler temperatures, with minimums around 7°C (44°F) and average highs reaching 32°C (89°F), while July showcases warmer temperatures, with minimums at 15°C (60°F) and an average maximum of 33°C (91°F). Rainfall is more abundant in July, totaling 341 mm (13.4 in) with precipitation occurring on 25 days, compared to September's 194 mm (7.6 in) over 19 days. Humidity levels remain relatively high in both months, with September at 89% and July slightly higher at 92%. For more specific information, check out Nagano weather in July.
Comparing the weather in September to August reveals a notable shift in temperature and precipitation patterns. In September, temperatures range from a minimum of 7°C (44°F) to a maximum of 32°C (89°F), with an average of 19°C (67°F). This is considerably cooler than August, which boasts a minimum of 11°C (52°F), an average of 24°C (75°F), and a peak of 35°C (95°F). Additionally, September experiences slightly less precipitation at 194 mm (7.6 in) over 19 days, compared to August's 198 mm (7.8 in) spread over 23 days. Humidity remains high in both months, with September at 89% and August at 92%. For more details on August's weather, check out Nagano weather in August.
In comparing the weather of September and October, notable changes can be observed. September boasts a warmer range of temperatures, with a minimum of 7°C (44°F) and an average high reaching 32°C (89°F), while October cools down significantly, featuring a minimum of 2°C (36°F) and an average high of 28°C (82°F). Humidity remains fairly consistent between the two months, with September at 89% and October at 87%. In terms of precipitation, October sees a slight increase to 217 mm (8.5 in) over 18 days compared to September's 194 mm (7.6 in) across 19 days. For those looking for detailed insights, you can check Nagano weather in October.
September and November present contrasting weather patterns, reflecting the transition from late summer to autumn. In September, temperatures range from a mild minimum of 7°C (44°F) to a hot maximum of 32°C (89°F), with an average of 19°C (67°F). This month is also marked by high humidity at 89% and significant rainfall, with 194 mm (7.6 in) of precipitation over 19 days. Conversely, November experiences a considerable drop in temperatures, featuring a minimum of -8°C (19°F) and an average of only 7°C (44°F), while still reaching a maximum of 21°C (70°F). Precipitation decreases to 94 mm (3.7 in) over 15 days, accompanied by slightly lower humidity at 85%. This shift highlights the distinctive characteristics of both months and their respective climates. For more details, you can check out Nagano weather in November.
In September, the weather is characterized by warm temperatures, with a minimum of 7°C (44°F) and an average of 19°C (67°F), peaking at a maximum of 32°C (89°F). This month experiences relatively high humidity at 89% and significant rainfall, totaling 194 mm (7.6 in) over 19 days. In contrast, December brings much colder conditions, with temperatures ranging from a minimum of -10°C (14°F) to a maximum of 19°C (66°F) and an average of just 1°C (34°F). Although the precipitation levels are slightly lower at 151 mm (6.0 in) over 20 days, the humidity remains high at 86%. For those interested in more specifics, check out Nagano weather in December.
As summer transitions into autumn, September in Nagano presents a delightful mix of warmth and freshness. With average temperatures hovering around a moderate 19°C (67°F), you can expect pleasantly mild days that starkly contrast the intense heat of July and August. However, don’t forget your umbrella; the month registers a significant 194 mm of rainfall spread over about 19 days, contributing to the area's lush greenery. The high humidity of 89% also adds a subtle richness to the air, making early fall in Nagano feel alive with a gentle energy. For those interested in a more detailed look at Nagano's climate patterns, visit Nagano Climate.