September Weather in Hachimantai, Japan

Last updated: August 21, 2025

In Hachimantai, Japan, September presents a captivating blend of weather conditions, characterized by a maximum temperature of 31°C (88°F) and an average of 18°C (64°F), providing a warm backdrop for early autumn adventures. However, visitors should prepare for variability, as temperatures can dip to a cool 3°C (38°F) at night. The month also sees 114 mm (4.5 in) of precipitation over 13 days, contributing to a refreshing atmosphere but necessitating an umbrella for those exploring the picturesque landscapes. With humidity levels at 86%, the environment offers a unique feel, enhancing the vibrant hues of the changing foliage while reminding travelers to stay hydrated on their explorations.

September Temperature in Hachimantai

In September, Hachimantai, Japan transitions into a delightful autumn, with temperatures ranging from a cool 3°C (38°F) at night to a warm 31°C (88°F) during the day. This month boasts an average temperature of 18°C (64°F), marking a noticeable shift from the warmth of summer, where highs reached up to 33°C (92°F) in August. As the days begin to shorten and the air crisps, the pleasant warmth persisting from the summer months gradually gives way to the chill of impending fall. Notably, September serves as a bridge between the vibrant heat of summer and the brisk coolness that defines October, making it a captivating time to experience Hachimantai's natural beauty amidst changing foliage.

September Weather in Hachimantai: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Hachimantai, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Hachimantai, September typically has an average temperature of {2}°C ({3}°F), with highs reaching up to {4}°C ({5}°F) and lows dropping to around {6}°C ({7}°F).
JanFebMarAprMayJunJulAugSepOctNovDec242535445662707264534129
Data source: Temperature data for Hachimantai generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Hachimantai

In September, Hachimantai experiences a notable shift in its precipitation patterns, with an average of 114 mm (4.5 in) of rainfall over 13 days. This marks a slight decrease from the summer months, where July and August saw significant rainfall of 155 mm (6.1 in) and 145 mm (5.7 in), respectively. However, September remains relatively wet, maintaining a balance between the heavy summer rains and the drier autumn months that follow. As the region transitions towards October, where precipitation spikes again to 152 mm (6.0 in) but over fewer days, this month's rainfall subtly foreshadows the upcoming seasonal changes, reminding residents and travelers alike of Japan's dynamic climate.

September Precipitation Trends in Hachimantai

The chart displays monthly precipitation patterns in Hachimantai, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Hachimantai, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec6284981191001131551451141526688
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Hachimantai

In September, Hachimantai, Japan experiences a significant transition in humidity levels, with the average reaching 86%. This figure marks a slight decline from the peak summer months of July and August, where humidity soared to 92%. As autumn approaches, the air becomes a bit crisper, yet still retains considerable moisture, echoing the patterns of the preceding months. The trend suggests a gradual tapering off from the intensively humid summer, yet humidity levels remain higher than those typically observed in the spring months, which hover around 75-80%. Overall, September serves as a bridge between the heat of summer and the cooler, more moderate conditions of fall, reflecting Hachimantai's unique climate rhythm.

September Average Humidity in Hachimantai

This chart illustrates the average monthly humidity levels in Hachimantai, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Hachimantai is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec80%79%77%75%80%87%92%92%86%82%79%80%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Hachimantai

In September, Hachimantai, Japan experiences a UV Index of 9, indicating a very high level of ultraviolet radiation, with a burn time of only 15 minutes. This trend reflects a slight decline from the intense extreme conditions in the peak summer months of June and August, where the UV Index soared to 11. As autumn approaches, the UV exposure remains significant, urging residents and visitors alike to take necessary precautions against sunburn. With this high UV index, it's essential to wear protective clothing, apply sunscreen, and seek shade during the peak hours of sunlight. For more detailed information on UV levels throughout the year, visit Hachimantai UV Index.

Maximum UV Index Levels in Hachimantai for September

The chart shows the monthly maximum UV Index (UVI) for Hachimantai in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Hachimantai typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec346891110119643
Data source: Hachimantai September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

September Sunshine in Hachimantai

September in Hachimantai, Japan, is a delightful transition month, basking in 241 hours of sunshine. As summer's warmth gently fades, it follows a peak in May with its impressive 288 hours, showcasing how the region flourishes under the sun. Sunlight starts to decrease as October approaches, but September still offers ample bright days, strategically nestled between the vibrant summer months and the cooler, cloudier autumn ahead. This prevailing sunshine not only highlights Hachimantai's natural beauty but also invites outdoor enthusiasts to enjoy hiking and exploring before the winter chill sets in.

Monthly Sunshine Duration in Hachimantai: September Highlighted

The September sunshine duration represents the total number of hours Hachimantai experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec152h200h250h258h288h272h269h254h241h211h195h182h
Data source: Hachimantai September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Hachimantai During September

In Hachimantai, Japan, the likelihood of sunny weather in September hovers around 29%, which reflects a slight uptick from the summer months when sunshine dips to a mere 17% in August. This trend represents a gradual transition from the humid summer season to the more temperate autumn months. Interestingly, as the year progresses, the chances of sunshine generally improve post-summer, with October showing a 34% likelihood and November at 37%. While September may not boast the highest probabilities for bright days, it serves as a bridge to clearer and sunnier days ahead, making it a unique time to experience Hachimantai's enchanting landscapes.

Percentage of Sunny Days in September in Hachimantai

The chart illustrates the percentage of sunny days in Hachimantai throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Hachimantai experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec31%38%30%41%26%28%26%17%29%34%37%31%
Data source: Hachimantai September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Hachimantai in September

In Hachimantai, Japan, the transition from summer to autumn is beautifully marked by a gradual decline in daylight hours throughout September, where the sun graces the horizon for around 12 hours each day. After basking in the long, sun-drenched days of June and July, which enjoy a consistent 14 hours of daylight, September signals a shift as daylight begins to wane. The month retains a balance with 12 hours of daylight, offering a softer light that highlights the stunning autumnal colors emerging from the surrounding landscapes. As the days shorten further into October, marking the onset of winter, the gradual decrease in sunlight emphasizes the rhythm of nature, preparing for the colder months ahead.

Average Daylight Hours in Hachimantai for September

The chart illustrates the variation in daylight duration in Hachimantai throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 40m10h 40m11h 56m13h 15m14h 22m14h 56m14h 39m13h 40m12h 25m11h 7m9h 58m9h 22m
Data source: Hachimantai daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Hachimantai

As September arrives in Hachimantai, Japan, the gentle whisper of the wind provides a soothing transition into autumn. With an average speed of 2.3 m/s (5 mph), the winds are a subtle shift from the more robust breezes of January through March, which hover around 3.1 to 3.8 m/s (7 to 8 mph). This gradual decline in wind speed — peaking in the winter months and softening through summer — reflects a calming lull as nature prepares for seasonal change. Interestingly, July and August witness the lowest winds, reaching only 1.8 m/s (4 mph). By September, however, the gentle currents serve as a reminder that the vibrant colors of autumn are approaching, ushering in a serene yet invigorating atmosphere, perfect for enjoying the natural beauty of this picturesque region.

Average September Wind Speed in Hachimantai

The chart displays monthly wind speed patterns in Hachimantai, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec3.13.83.23.12.92.11.82.22.3 m/s2.32.73.2
Data source: Hachimantai September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Hachimantai Compares to Other Months

Weather in Hachimantai varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Hachimantai, 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 3°C (38°F) to a warm 31°C (88°F), with an average of 18°C (64°F). The month experiences significant rainfall, totaling 114 mm (4.5 in) over approximately 13 days, accompanied by high humidity at 86%. In contrast, January brings much colder conditions, with temperatures plunging to a minimum of -18°C (1°F) and a maximum of only 5°C (41°F), averaging -4°C (24°F). Precipitation in January is lower, at 62 mm (2.4 in) over about 11 days, and humidity is slightly lower at 80%. The dramatic difference in temperatures and overall climate highlights the shift from late summer to deep winter. For more details, visit Hachimantai weather in January.

September and February present starkly contrasting weather conditions. In September, temperatures range from a mild 3°C (38°F) to a warm 31°C (88°F), resulting in an average of 18°C (64°F). The month is characterized by high humidity at 86% and notable precipitation, totaling 114 mm (4.5 in) across 13 days. In contrast, February brings much colder weather, with temperatures dropping as low as -20°C (-4°F) and averaging -4°C (26°F). The maximum temperature reaches just 8°C (46°F), and while precipitation is slightly less at 84 mm (3.3 in), it occurs over a greater number of days, totaling 15. Despite the lower humidity of 79%, the chill of February stands in sharp opposition to the warmth and humidity of September. For more specific details on February weather, you can visit Hachimantai weather in February.

September and March present stark contrasts in weather. In September, temperatures range from a mild 3°C (38°F) to a warm 31°C (88°F), creating an overall average of 18°C (64°F). The month sees considerable rainfall, with 114 mm (4.5 in) spread over approximately 13 days, accompanied by high humidity levels at 86%. In contrast, March experiences much colder conditions, with temperatures ranging from a chilly -17°C (1°F) up to a modest 17°C (63°F), averaging just 2°C (35°F). This month has slightly less precipitation at 98 mm (3.9 in) over 14 days, and the humidity is lower at 77%. For a closer look at March weather specifics, check out Hachimantai weather in March.

When comparing the weather in September and April, several notable differences emerge. September generally presents a milder climate, with average temperatures ranging from a minimum of 3°C (38°F) to a maximum of 31°C (88°F), while April's temperatures can drop as low as -10°C (15°F), peaking at 23°C (73°F). April is also characterized by higher snowfall potential due to its colder temperatures, achieving an average of 7°C (44°F), whereas September enjoys relatively warmer conditions with an 18°C (64°F) average. Both months experience considerable precipitation, with September accumulating 114 mm (4.5 in) over 13 days, while April sees slightly more at 119 mm (4.7 in) over 17 days. Additionally, humidity levels are notably higher in September at 86%, compared to April's 75%. For a deeper look, you can check out Hachimantai weather in April.

September and May present distinct weather profiles, reflecting the transition from summer to autumn in September and the onset of spring in May. In September, temperatures can range from a chilly minimum of 3°C (38°F) to a warm maximum of 31°C (88°F), with an average of 18°C (64°F). This month is characterized by higher humidity at 86% and considerable precipitation of 114 mm (4.5 in) over 13 days. In contrast, May experiences slightly cooler temperatures, with a minimum of 2°C (35°F), an average of 13°C (56°F), and a maximum of 29°C (85°F). Although May has a similar number of rainy days, it receives slightly less precipitation, totaling 100 mm (3.9 in), with a lower humidity level of 80%. For more detailed information, check out Hachimantai weather in May.

When comparing the weather in September and June, we see some interesting similarities and differences. September generally has a wider temperature range, with a minimum of 3°C (38°F) compared to June's 5°C (42°F), and a maximum reaching 31°C (88°F), slightly warmer than June's peak of 29°C (84°F). Both months experience similar averages, with September averaging 18°C (64°F) and June at 17°C (63°F). Precipitation levels are almost identical, with September receiving 114 mm (4.5 in) and June at 113 mm (4.4 in) over about 13 days. Humidity remains high in both months, with September at 86% and June slightly higher at 87%. For those interested in exploring more about June weather, you can check this link: Hachimantai weather in June.

In comparing the weather of September and July, we can see notable differences in temperature and precipitation. September experiences a broader temperature range, with minimums reaching 3°C (38°F) and maximums peaking at 31°C (88°F), while the average temperature is around 18°C (64°F). In contrast, July is generally warmer, with minimums at 12°C (55°F) and a maximum of 32°C (90°F), along with a higher average temperature of 21°C (71°F). However, July also sees more rainfall, with 155 mm (6.1 in) over 18 days compared to September's 114 mm (4.5 in) over 13 days. Additionally, humidity levels are higher in July at 92%, compared to 86% in September. For more detailed information on July weather, visit Hachimantai weather in July.

September's weather shows a noticeable drop in minimum temperatures compared to August, with lows of 3°C (38°F) versus August's 10°C (50°F). The average temperature also declines, sitting at 18°C (64°F) in September, down from August's warmer average of 22°C (72°F). Despite experiencing slightly less rainfall in September at 114 mm (4.5 in) over 13 days, compared to August's 145 mm (5.7 in) over 16 days, both months exhibit high humidity levels, although September is marginally lower at 86% compared to August’s 92%. For more insights, you can visit Hachimantai weather in August.

September and October present distinct transitions in weather. September boasts a wider temperature range, with minimums of 3°C and maximums reaching up to 31°C, averaging around 18°C. The month experiences significant rainfall with a total of 114 mm across 13 days, alongside high humidity at 86%. In contrast, October sees a drop in temperatures, with minimums dipping to 0°C and an average of just 11°C, while the maximum temperature is noticeably lower at 26°C. The month is wetter, accumulating 152 mm of precipitation over 11 days, but the humidity is slightly reduced at 82%. For a detailed look at the October conditions, check out Hachimantai weather in October.

September and November present a stark contrast in weather conditions. September typically boasts a much warmer climate, with average temperatures reaching 18°C (64°F) and highs of up to 31°C (88°F). In this month, precipitation is relatively high at 114 mm (4.5 in) over 13 days, coupled with high humidity at 86%. In contrast, November experiences a significant drop in temperatures, with an average of 5°C (41°F) and maximums only reaching 18°C (65°F), while the minimums plunge to -12°C (11°F). The precipitation in November is lower, at 66 mm (2.6 in) over 11 days, and it features a more moderate humidity level of 79%. For more specifics on the weather during this month, you can visit Hachimantai weather in November.

In September, temperatures in Hachimantai fluctuate significantly, with a minimum of 3°C (38°F) and an average of 18°C (64°F), reaching a high of 31°C (88°F). The month is characterized by more humidity at 86%, alongside notable rainfall, amounting to 114 mm (4.5 in) over 13 days. In stark contrast, December brings a much colder climate, with a minimum temperature plunging to -12°C (10°F) and an average of -1°C (30°F), peaking at 12°C (55°F). Although December experiences slightly less precipitation, at 87 mm (3.4 in) over 15 days, humidity remains relatively high at 80%. For more detailed information about the weather in December, you can check out Hachimantai weather in December.

Compare Hachimantai's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Hachimantai

September in Hachimantai brings a unique blend of warmth and moisture, distinguishing it from the drier summer months. As the transition into autumn begins, temperatures can still reach a maximum of 31°C (88°F) during the day, but the cool nights drop to a refreshing 3°C (38°F). This month is characterized by its higher humidity level at 86% and increased precipitation, with about 114 mm (4.5 in) falling over 13 days. The result is a lush scenery that invites both visitors and nature lovers to experience the vibrant landscapes of Hachimantai as they prepare for the impending fall. For a deeper dive into the seasonal patterns, check out Hachimantai Climate.