Last updated: August 21, 2025
In September, Yamanashi, Japan experiences a delightful transition in its weather patterns, where average temperatures hover around 18°C (65°F), peaking at a warm 31°C (87°F). With a minimum temperature dipping to 9°C (49°F), the month offers a refreshing range for outdoor activities. However, residents and visitors should prepare for rain, as precipitation totals reach around 208 mm (8.2 in) across approximately 22 days, resulting in humidity levels around a notable 86%. This blend of warmth and moisture fosters a vibrant natural landscape, making September an intriguing month to explore the beauty of Yamanashi.
In September, Yamanashi, Japan, experiences a delightful transition as summer begins to wane. With minimum temperatures averaging around 9°C (49°F) and maximums reaching a comfortable 31°C (87°F), the month showcases a perfect blend of warmth and coolness. This moderate climate, with an average temperature of 18°C (65°F), encourages outdoor activities amidst the beautiful autumn foliage starting to emerge. As the nights grow cooler, it marks a shift from the peak summer heat, creating an inviting atmosphere ideal for exploring the scenic landscapes and enjoying seasonal delights. Overall, September in Yamanashi offers a harmonious balance, making it a prime time for visitors to experience the region's natural beauty.
In September, Yamanashi experiences a significant increase in precipitation, recording 208 mm (8.2 in) over 22 days. This marks a peak following the summer months, as the region transitions from the sweltering heat of August, which saw 190 mm (7.5 in), to a more pronounced wet season that sets the stage for October's even higher totals. The pattern suggests a late-summer surge in rainfall, which is typical as the typhoon season approaches, leading to intensified moisture and cooler temperatures. This trend exemplifies Yamanashi's dynamic climate, where the onset of autumn begins to reshape the landscape with vibrant colors and refreshed, thriving ecosystems.
As summer fades into autumn, September in Yamanashi, Japan experiences a noticeable shift in humidity levels, settling at a comfortable 86%. This marks a slight decline from the peak of 93% in July and 90% in August, ushering in a more pleasant atmosphere as the region prepares for the crisp fall air. Interestingly, the month's humidity remains comparatively high, only slightly lower than the earlier summer months, and is noticeably higher than the October average of 83%. This trend highlights the transition from the oppressive heat of summer to the refreshing coolness of autumn, making September a unique bridge between the two seasons in Yamanashi's climatic tapestry.
In September, Yamanashi, Japan, experiences a UV Index of 10, placing it in the very high exposure category. As summer winds down, UV levels begin to decrease from the extreme highs of July and August, but caution is still necessary, with a burn time of just 15 minutes for unprotected skin. This trend of high UV readings during the warmer months highlights the importance of sun protection even as the season changes. With a strong UV presence throughout the summer and into early autumn, residents and visitors alike should remain vigilant about their sun safety. For more detailed insights, check the Yamanashi UV Index.
UV Risk Categories
September in Yamanashi, Japan, offers a delightful blend of mild temperatures and vibrant colors, with 229 hours of sunshine lighting up the month. While the days begin to shorten, the sunshine hours reflect a gentle decline from the summer peak of 275 hours in August, embodying the transition into fall. This gradual reduction highlights the region's overall sunny disposition throughout the year, with peak brightness occurring from May to August. Interestingly, as the vibrant foliage of autumn begins to appear, Yamanashi still enjoys more sunlight this month than in January or early spring, making September a perfect time for outdoor adventures and enjoying the picturesque landscapes.
In Yamanashi, Japan, the likelihood of encountering sunny weather takes a notable dip in September, with only 17% chance of sun. This month marks the transition into autumn, following a summer where sunny days are sporadic, peaking at just 23% in August. As the year progresses, the chances of sunny weather begin to recover, with October reflecting a more promising 41% likelihood. Overall, the trend reveals that while sunny days are relatively scarce during September, they increase as autumn deepens, offering glimpses of brightness ahead.
As summer gently transitions to autumn, September in Yamanashi, Japan, sees a notable shift in daylight duration, with the sun gracing the sky for 12 hours. This marks a gradual decline from the long, sun-drenched days of summer, where daylight peaked at 14 hours in June and July. The change signals the start of a cooler season, where the lush green landscapes begin to take on warmer hues. In the months leading up to September, daylight increased steadily, reaching its zenith in late spring, followed by a slow descent as the year progresses towards winter. This rhythm of daylight reflects the region’s natural beauty and the cyclical dance of the seasons, inviting residents and visitors alike to savor the light while it lasts.
In September, Yamanashi experiences a gentle breeze with an average wind speed of 1.4 m/s (3 mph), marking a subtle transition into the cooler autumn months. Following the warmer summer, where wind speeds hovered around 1.5 m/s (3 mph), the September winds reflect a slight dip reminiscent of the calmness that settles before the vibrant fall colors emerge. This month stands out as slightly less breezy compared to April and November, which both average 1.8 m/s (4 mph), suggesting that the changing season brings a certain tranquility to the region’s atmospheric dance. As the winds begin to shift, they not only signal the impending harvest but also offer a refreshing reprieve, inviting locals and visitors alike to embrace the serene beauty of Yamanashi during this transitional time.
Weather in Yamanashi varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Yamanashi, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present a striking contrast in weather characteristics. In September, temperatures start at a mild minimum of 9°C (49°F) and can rise to a warm 31°C (87°F), making it a month with vibrant warmth, albeit accompanied by significant rainfall of 208 mm (8.2 in) across 22 days and high humidity levels of 86%. In contrast, January showcases a much colder landscape, with temperatures plunging to a minimum of -17°C (2°F) and peaking at a maximum of just 11°C (52°F). With only 48 mm (1.9 in) of precipitation spread over 6 days, January is notably drier and less humid, registering at 76%. For more detailed insights into January weather, you can check Yamanashi weather in January.
September and February present starkly different weather conditions. In September, temperatures range from a mild 9°C (49°F) at night to a warm 31°C (87°F) during the day, with an average of 18°C (65°F). The month is characterized by high humidity at 86% and substantial rainfall, with 208 mm (8.2 in) falling over 22 days. In contrast, February experiences much colder weather, with temperatures dipping as low as -12°C (11°F) and averaging around 0°C (33°F) during the day, peaking at 17°C (63°F). The month is marked by much lower precipitation, totaling only 58 mm (2.3 in) over 9 days, and a humidity level of 74%. For more detailed insights, you can explore Yamanashi weather in February.
September and March present contrasting weather patterns. September boasts a warmer climate with temperatures ranging from a cool 9°C (49°F) to a hot 31°C (87°F), resulting in an average of 18°C (65°F) and considerable humidity at 86%. However, it also experiences significant rainfall, with 208 mm (8.2 in) over 22 days. In contrast, March is much cooler, with temperatures ranging from a low of -7°C (21°F) to a high of 21°C (70°F) and an average of just 5°C (41°F). The month is drier, receiving 144 mm (5.7 in) of precipitation over 13 days and a lower humidity of 70%. For a detailed look at the weather specifics in March, you can check Yamanashi weather in March.
In comparing the weather of September and April, we see significant differences in temperature and humidity. September tends to be much warmer, with average temperatures around 18°C (65°F) and maximums reaching up to 31°C (87°F), while April offers a cooler experience with averages about 9°C (48°F) and maximums of 25°C (78°F). Additionally, September experiences higher humidity levels at 86% compared to April's 74%, contributing to a more sultry feel. Rainfall also varies, with September receiving 208 mm (8.2 in) over 22 days, while April has a more moderate 138 mm (5.4 in) spread over just 15 days. For a deeper look into April weather specifically in Yamanashi, you can check Yamanashi weather in April.
In comparing the weather between September and May, September tends to be warmer, with average temperatures ranging from a cool 9°C (49°F) at night to a hot 31°C (87°F) during the day, while May sees a more moderate range from 0°C (33°F) to 28°C (82°F). Rainfall is more frequent in September, with 208 mm (8.2 in) over 22 days, compared to May's 148 mm (5.8 in) over just 15 days. Interestingly, humidity levels are slightly higher in September at 86%, compared to 81% in May. For a more detailed understanding of May's weather, you can visit Yamanashi weather in May.
September and June exhibit similar temperature ranges, but September tends to be slightly warmer, with average temperatures reaching 18°C (65°F) compared to June's average of 17°C (63°F). Additionally, September sees a higher maximum temperature of 31°C (87°F), making it the warmer month overall. However, both months experience significant precipitation, with September receiving 208 mm (8.2 in) over 22 days, while June has a total of 179 mm (7.1 in) spread across 19 days. Humidity is also high in both months, with September at 86% and June slightly higher at 88%. For a detailed overview of June weather, you can refer to Yamanashi weather in June.
September and July exhibit notable differences in weather patterns. September’s temperatures range from a minimum of 9°C (49°F) to a maximum of 31°C (87°F), with an average of 18°C (65°F), while July is slightly warmer, featuring a minimum of 13°C (56°F), an average of 21°C (70°F), and a maximum of 32°C (90°F). In terms of precipitation, September sees 208 mm (8.2 in) over approximately 22 days, which is somewhat less than July’s heavier rainfall of 320 mm (12.6 in) across 24 days. Furthermore, humidity is higher in July at 93%, compared to September’s 86%. For more insights, you can explore Yamanashi weather in July.
In comparing the weather between August and September, we notice that September tends to be cooler overall with average temperatures ranging from a minimum of 9°C (49°F) to a maximum of 31°C (87°F), while August boasts warmer averages with a minimum of 12°C (55°F) and a maximum of 33°C (91°F). Additionally, September experiences slightly more precipitation at 208 mm (8.2 in) over 22 days, compared to August's 190 mm (7.5 in) over 23 days. Humidity remains high in both months, peaking at 86% in September and 90% in August, making both months feel quite humid. For more insights into August weather, check out Yamanashi weather in August.
In September, the weather is characterized by warm temperatures, with a minimum of 9°C (49°F) and a maximum of 31°C (87°F), resulting in an average of 18°C (65°F). This month also sees a significant amount of rainfall, accumulating to 208 mm (8.2 in) over 22 days, coupled with high humidity levels of 86%.
Conversely, October brings a notable drop in temperatures, with a minimum of 2°C (35°F) and an average of 13°C (55°F), peaking at 27°C (80°F). Rainfall increases to 324 mm (12.8 in) over 19 days, while humidity slightly decreases to 83%. For more detailed information on the weather conditions during October, you can visit Yamanashi weather in October.
September and November present contrasting weather conditions. In September, temperatures range from a mild 9°C (49°F) to a warm 31°C (87°F), with an average of 18°C (65°F). The month also experiences considerable rainfall, with 208 mm (8.2 in) falling over 22 days, coupled with high humidity levels averaging 86%. In contrast, November brings a significant drop in temperatures, with a minimum of -4°C (26°F), an average of 7°C (45°F), and a maximum of 19°C (66°F). This month sees much less rainfall, totaling just 56 mm (2.2 in) over 10 days and a decrease in humidity to around 80%. For more detailed insights, check out Yamanashi weather in November.
September and December present distinct contrasts in weather. In September, temperatures can range from a mild 9°C (49°F) at night to a warm 31°C (87°F) during the day, with an average of 18°C (65°F). This month also experiences considerable rainfall, with 208 mm (8.2 in) over 22 days, contributing to a high humidity level of 86%. Conversely, December brings much colder temperatures, with a minimum of -8°C (17°F) and an average of just 2°C (36°F), peaking at 18°C (65°F) on warmer days. The month is drier, seeing only 52 mm (2.1 in) of precipitation over 8 days, and a lower humidity level of 78%. For more detailed information, check out Yamanashi weather in December.
As September unfolds in Yamanashi, the transition from summer to autumn is palpable, with temperatures that balance warmth and coolness. Unlike the sizzling highs of July and August, the maximum temperature dips, while the humidity remains high, creating a comfortable yet occasionally damp atmosphere. Frequent rain showers characterize the month, contributing to the notable precipitation over 22 days, which sets September apart from the drier summer months. This blend of warm days and refreshing rains highlights the region's unique climate, giving way to vibrant fall foliage as the season progresses. For more insights into the weather patterns in Yamanashi, check out Yamanashi Climate.