September Weather in Nikko, Japan

Last updated: August 21, 2025

September in Nikko, Japan offers a stunning transition from summer to autumn, with temperatures peaking at a warm 29°C (84°F) during the day and dropping to a cool 6°C (43°F) at night. The average temperature hovers around 18°C (65°F), providing a pleasant climate for outdoor exploration. However, visitors should be prepared for the frequent rain, as the month sees 239 mm (9.4 in) of precipitation spread over 25 days, creating a humid atmosphere with levels reaching 89%. Despite the drizzle, the lush landscapes of Nikko are particularly vibrant this time of year, beckoning travelers to immerse themselves in its natural beauty.

September Temperature in Nikko

As September unfolds in Nikko, Japan, temperatures begin to reflect the shift toward autumn. With a minimum of 6°C (43°F) and an average of 18°C (65°F), the month marks a noticeable drop from the peak summer warmth, where highs have reached an inviting 29°C (84°F). This transition offers a refreshing ambiance, perfect for enjoying outdoor activities amidst stunning foliage. September is an ideal time to explore Nikko's natural beauty as the crisp air and moderate temperatures create a comfortable backdrop, inviting travelers to immerse themselves in the region's vibrant landscapes just before the chilly embrace of October sets in.

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

The chart illustrates September temperature patterns in Nikko, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Nikko, 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).
JanFebMarAprMayJunJulAugSepOctNovDec293038465763707365554434
Data source: Temperature data for Nikko generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Nikko

In September, Nikko experiences significant rainfall, with 239 mm (9.4 in) falling over 25 days. This amount is a sharp decline from the record-breaking 345 mm (13.6 in) of July, yet it still reflects the lingering effects of the summer monsoon season. As the landscape transitions from the lush greens of summer to the early hues of autumn, this sustained precipitation helps nurture the vibrant foliage that Nikko is renowned for. This month serves as a bridge, moderating between the heavy rains of summer and the drier conditions that typically begin in October, where precipitation rises again to 279 mm (11.0 in). The overall trend reveals a steady cycle of rainy days, creating a dynamic environment for both nature and visitors alike.

September Precipitation Trends in Nikko

The chart displays monthly precipitation patterns in Nikko, 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 Nikko, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec55531421431762253452732392796168
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Nikko

In Nikko, Japan, September brings a slight dip in humidity, measuring at 89% after the sweltering summer months of July and August, which both recorded 92% humidity. This moderate decrease indicates a transitional phase as the region shifts from the intense humidity of summer to the cooler autumn temperatures. Interestingly, prior to September, June also experiences high humidity at 88%, suggesting a trend of lingering moisture throughout the late summer. As the year progresses, Nikko typically maintains a notable level of humidity, with values generally ranging from 78% in April to 92% in July and August, creating a humid yet comfortable atmosphere that is characteristic of this beautiful area.

September Average Humidity in Nikko

This chart illustrates the average monthly humidity levels in Nikko, 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 Nikko is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%87%81%79%81%88%92%92%89%87%85%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Nikko

In September, Nikko experiences a UV Index of 10, categorizing exposure as very high, with a burn time of just 15 minutes. This marks a gradual decrease from the extreme UV levels of the summer months, while still prompting caution for sun exposure. As the season transitions, September serves as a reminder that UV radiation remains significant, making protective measures essential for outdoor activities. With this monthly trend, it's clear that while the peak intensity of summer may be past, UV awareness should remain at the forefront. For detailed information, visit Nikko UV Index.

Maximum UV Index Levels in Nikko for September

The chart shows the monthly maximum UV Index (UVI) for Nikko 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 Nikko typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec46891011111110753
Data source: Nikko 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 Nikko

As summer gently fades, September in Nikko, Japan, brings a delicate balance of warmth and light, with 230 hours of sunshine illuminating the stunning landscapes. Following the sun-drenched days of August, which boasted a vibrant 274 hours, September sees a natural decline in hours, mirroring the gradual transition into autumn. This month stands out as a time when nature begins to don its fall attire, creating a picturesque backdrop perfect for exploring the rich history and breathtaking scenery of the region. Interestingly, September's sunshine hours are higher than the upcoming months, such as October’s 209 hours and November’s 229 hours, hinting at the last gasp of summer warmth before the cool embrace of fall sets in. Whether you're drawn by the serene temples or the vibrant foliage, September offers a harmonious blend of light and beauty in Nikko.

Monthly Sunshine Duration in Nikko: September Highlighted

The September sunshine duration represents the total number of hours Nikko 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.
JanFebMarAprMayJunJulAugSepOctNovDec184h233h266h278h284h271h241h274h230h209h229h224h
Data source: Nikko September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Nikko During September

In Nikko, Japan, September marks the tail end of summer, and while the likelihood of sunny weather hovers at 20%, it reflects a broader trend of diminishing sunshine as the year progresses. Following the sweltering months of July and August, which also boast a 20% chance of sunshine, September transitions into the cooler embrace of autumn. This month stands out as part of a pattern where the chances of sunny days experience a notable dip during the rainy season, peaking again in October at 41% and climbing toward the winter. If you're planning a visit, be prepared for variability and perhaps a little sprinkle, but remember, the charming landscapes of Nikko always have something magical to offer, rain or shine.

Percentage of Sunny Days in September in Nikko

The chart illustrates the percentage of sunny days in Nikko 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 Nikko experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec40%48%33%45%24%17%20%20%20%41%53%46%
Data source: Nikko September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Nikko in September

As the warm embrace of summer begins to wane, September in Nikko, Japan, offers a gentle transition with approximately 12 hours of daylight. This month marks a subtle decline from the peak of 14 hours during the summer, reflecting the gradual shift toward autumn. The daylight duration has already begun to decrease from the vibrant days of high summer, leading into the cooler months ahead. Following September, the daylight hours continue to taper off, with October and November bringing just 11 and 10 hours, respectively. This cyclical rhythm showcases the beautiful balance of nature, as each month unfolds a unique blend of light and shadow, ultimately guiding Nikko from the lushness of summer into the serene charm of fall.

Average Daylight Hours in Nikko for September

The chart illustrates the variation in daylight duration in Nikko throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 56m10h 49m11h 57m13h 8m14h 7m14h 37m14h 22m13h 30m12h 23m11h 13m10h 12m9h 40m
Data source: Nikko daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Nikko

As September arrives in Nikko, Japan, the gentle breeze begins to soften, with average wind speeds dipping to 1.4 m/s (3 mph). This subtle shift marks a departure from the lively gusts of summer, as the region transitions towards the serene embrace of autumn. Throughout the year, wind speeds have generally fluctuated; notably, winter months like January and December showcase stronger winds at around 2.2 m/s and 2.3 m/s, while the summer months linger at their calmest. In September, the mild winds reflect the peaceful ambiance of the landscape, creating a perfect backdrop for visitors to savor the stunning fall foliage and tranquil temples that Nikko is renowned for.

Average September Wind Speed in Nikko

The chart displays monthly wind speed patterns in Nikko, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.22.72.32.31.91.51.21.51.4 m/s1.71.82.3
Data source: Nikko September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Nikko Compares to Other Months

Weather in Nikko varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Nikko, focusing on differences in temperature, rainfall, humidity, and UV levels.

September and January display stark contrasts in weather conditions. September boasts a mild climate with average temperatures ranging from 6°C (43°F) to a maximum of 29°C (84°F), complemented by significant rainfall of 239 mm (9.4 in) over 25 days, and a high humidity of 89%. In contrast, January brings a much colder environment, with temperatures dropping to a minimum of -12°C (11°F) and only reaching an average of -2°C (29°F), accompanied by minimal precipitation of 55 mm (2.2 in) across 11 days and slightly lower humidity at 88%. For more detailed insights into this winter month, you can check out Nikko weather in January.

In September, the weather features a wide temperature range, with minimums around 6°C (43°F) and maximums reaching 29°C (84°F), resulting in an average of 18°C (65°F). This month is also characterized by significant precipitation, totaling 239 mm (9.4 in) over approximately 25 days, along with high humidity levels at 89%. In contrast, February brings much colder conditions, with temperatures dropping to a minimum of -15°C (5°F) and averaging at -1°C (30°F), while maximums only reach up to 16°C (61°F). Precipitation in February is much lower, totaling 53 mm (2.1 in) across around 11 days, coupled with a slightly lower humidity of 86%. For a more detailed view of February weather, you can visit Nikko weather in February.

September and March present contrasting weather patterns. In September, temperatures range from a mild minimum of 6°C (43°F) to a warm maximum of 29°C (84°F), with an average of 18°C (65°F). This month is also characterized by high humidity at 89% and significant rainfall of 239 mm (9.4 in) over 25 days. In contrast, March experiences much colder conditions, with minimum temperatures plummeting to -11°C (13°F) and an average of only 4°C (39°F). While it does warm up to a maximum of 19°C (67°F), March has considerably less precipitation, totaling 142 mm (5.6 in) across 14 days, and a lower humidity level at 81%. For more detailed insights about March weather specifically, you can check Nikko weather in March.

September and April exhibit notably different weather patterns. In September, temperatures range from a cool 6°C (43°F) to a warm 29°C (84°F), with an average of 18°C (65°F). The month experiences significant rainfall, with 239 mm (9.4 in) spread across 25 days, resulting in a high humidity level of 89%. In contrast, April is milder, featuring temperatures from a low of -4°C (24°F) to a pleasant high of 24°C (76°F), and an average of 8°C (47°F). Precipitation is also less intense, totaling 143 mm (5.6 in) over 15 days, with a lower humidity of 78%. For more detailed insights, you can check Nikko weather in April.

September and May exhibit distinct weather patterns that influence their respective climates. In September, temperatures range from a chilly 6°C (43°F) to a warm 29°C (84°F), with an average of 18°C (65°F). This month is marked by high humidity at 89% and frequent rainfall, totaling 239 mm (9.4 in) over 25 days. In contrast, May experiences cooler temperatures, with a minimum of 1°C (34°F) and a maximum of 28°C (82°F), averaging around 14°C (57°F). The precipitation in May is less, at 176 mm (6.9 in) across 18 days, and humidity levels are slightly lower at 81%. For a more detailed view of what to expect during this time, check out Nikko weather in May.

September and June exhibit somewhat similar weather patterns, though with notable differences. In September, temperatures range from a minimum of 6°C (43°F) to a maximum of 29°C (84°F), with an average of 18°C (65°F). This month also sees higher precipitation, with 239 mm (9.4 in) spread over 25 days and humidity levels at 89%. In contrast, June has slightly cooler temperatures, ranging from a minimum of 7°C (44°F) to a maximum of 27°C (81°F), with an average of 17°C (63°F). This month experiences a bit less rainfall, totaling 225 mm (8.8 in) across 21 days and maintaining a humidity level of 88%. Overall, while both months are relatively humid with comparable temperatures, September tends to be wetter and warmer. For more specifics, you can check Nikko weather in June.

When comparing the weather in September and July, it’s clear that July tends to be warmer with average temperatures around 21°C (70°F) and maximums reaching 31°C (88°F), while September has a cooler average of 18°C (65°F) and highs of 29°C (84°F). Additionally, July experiences higher humidity at 92% compared to September's 89%. However, July also sees significantly more precipitation, with 345 mm (13.6 in) falling over 27 days, versus September's 239 mm (9.4 in) of rain over 25 days. For a closer look at July's weather patterns, you can check Nikko weather in July.

In comparing the weather of September and August, September experiences a noticeable drop in temperature, with minimums reaching 6°C (43°F) compared to August's milder 10°C (50°F). The average temperature in September is 18°C (65°F), significantly lower than August's warmer 23°C (73°F), while maximum temperatures also see a decline from 32°C (89°F) in August to 29°C (84°F) in September. Additionally, September has higher precipitation, totaling 239 mm (9.4 in) over 25 days, compared to August's 273 mm (10.7 in) across 26 days. Humidity levels remain fairly high in both months, with September at 89% and August slightly higher at 92%. For a detailed look at August weather patterns, you can visit Nikko weather in August.

September typically offers a broader range of temperatures, with a minimum of 6°C, an average of 18°C, and a maximum of 29°C. This month also sees considerable rainfall, with 239 mm falling over 25 days and a high humidity level of 89%. In contrast, October features cooler temperatures, with a minimum of 0°C, an average of 13°C, and a maximum of 25°C. While it experiences slightly higher precipitation at 279 mm over 19 days, the humidity remains relatively stable at 87%. For a more detailed look at October weather in Nikko, you can visit Nikko weather in October.

September and November present contrasting weather patterns. In September, temperatures range from a mild 6°C (43°F) at night up to a warm 29°C (84°F) during the day, with an average of 18°C (65°F). The month is quite wet, boasting a high precipitation amount of 239 mm (9.4 in) over 25 days, coupled with a humidity level of 89%. In comparison, November experiences a noticeable drop in temperatures, with lows dipping to -4°C (25°F) and average daytime highs reaching only 18°C (64°F). Precipitation significantly decreases to 61 mm (2.4 in) over just 7 days, and humidity holds steady at 85%. For more specific details about November weather patterns, check out Nikko weather in November.

September and December present contrasting weather conditions. In September, temperatures range from a low of 6°C (43°F) to a high of 29°C (84°F), with an average of 18°C (65°F). This month experiences significant rainfall, totaling 239 mm (9.4 inches) across 25 days, coupled with high humidity at 89%. In contrast, December sees much colder temperatures, ranging from a minimum of -11°C (12°F) to a maximum of 16°C (61°F) and an average of just 1°C (34°F). The precipitation drops considerably to 68 mm (2.7 inches) over 11 days, with humidity slightly lower at 86%. For more detailed information on December weather, check out Nikko weather in December.

Compare Nikko's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Nikko

As September rolls in, Nikko transforms into a vibrant landscape marked by cool breezes and a mosaic of autumn colors. Unlike the sweltering summer months, temperatures in September offer a refreshing average that invites outdoor exploration. However, be prepared for frequent rain, with nearly 30% of the month seeing precipitation, making it one of the wetter times of the year. The high humidity levels add to the richness of the atmosphere, creating a unique, refreshing experience. Whether you're hiking through lush forests or enjoying the serene temples, September's weather is a reminder that Nikko is a destination to cherish year-round. For a deeper dive into what to expect, visit Nikko Climate.