Nikko weather in September
September in Nikko: warm, soaked, with clean air — fine if you can take 23 rainy days.
Updated September 2026 · climate normals from ERA5 reanalysis
#6 of 12 months in Nikko · #957 of 1413 destinations to visit in September · comfort 70/100 (tier B)
- Days
- 24°C
- Nights
- 18°C
- Wet days
- 23
- Sun
- 7.5 h
- Humidity
- 88%
- Daylight
- 12 h

Traveller notes on Nikko in September
September here can be too foggy and wet for good visibility, and regulars say October and November both run drier - our row backs that with 241.5mm across 23 days at 87.9 percent humidity, easily this destination's wettest column of the ones we carry. The consolation is Kegon Falls itself: the volume of water is at its best now, and visitors who caught a clear late-September day call the falls robust and colourful with the season's first hints of colour already showing. Peak foliage in the upper park is a month or more away, mid to late October. Our temperature reads gently, 23.8C over 17.6C, with only 7.5 hours of sun a day standing behind that rain total. The record: an 8.4 kph wind and AQI 38.
Other months in Nikko
Regulars are specific the lower Toshogu area can turn cold and rainy with sleet even as the mountains above stay genuinely hard to predict, snow at higher elevations a real possibility - one memorable year even brought a snowstorm as late as April 1st. Our row backs that cold, genuinely wet read, 10.1C over -0.1C nights feeling as low as -4C, with a substantial 131.9mm of rain across 14.6 days and real snow, 32.4cm. Regulars are consistent Lake Chuzenji specifically runs colder and more exposed than the lower town, staying cold and crisp even late in the month. Thick coats, hats and gloves remain the standard advice throughout rather than an early-spring wardrobe. The record: humidity 73 percent, 8.5 hours of sun and a 13 kph wind.
The colour here is a question of altitude, not date. Regulars are blunt that the town and shrine area is mostly cedar and does not turn at all, so the autumn everyone comes for is up the Irohazaka road at Chuzenji and Kegon, and by late October that upper ground is in full colour. The cost is the same road: weekends are extremely crowded and the bus up to Oku Nikko can hold you for hours, so the advice is a weekday and a very early start. Light layers do it in October at 17.9C over 10.6C. Our row adds what the board leaves out - 197.7mm across 17.4 days and only 7 hours of sun - so this is a wet month to be planning a view in. The record: humidity 84 percent, a 9.2 kph wind and AQI 32.
For once our snow column is not describing a distant hillside: visitors to Nikko in early April report actual snow, very cold air around Kegon Falls, and at least one April storm that made roads impassable, which is what the 8.5cm in our row is. The split to plan around is inside the destination. Downtown Nikko is the mild part at 15.2C over 4.8C; up at Lake Chuzenji, several hundred metres higher, the mountains are still white and the woods still under snow while the town below is in spring. If the Fukiware-to-Chuzenji road closes there is a low route that adds about two hours. And regulars are blunt that this is not a cherry-blossom destination - Nikko is deciduous forest, not sakura. The record: 142.6mm across 14.9 days, 9.1 hours of sun and AQI 55.
The standing Japanese advice for June is that the tsuyu is bearable - light rain rather than torrential, warm rather than hot days, not raining every day, with the season usually starting around the 10th. Nikko is the place that advice under-describes. Our row carries 217.4mm across 22 precipitation days at 85 percent humidity, two days in three and ten millimetres on each, because this is mountain country rather than Tokyo. What goes first is the view: one June visitor could not see Kegon Falls at all for fog. What is at its best is the planting - the ajisai hydrangeas and the moss are the reason several regulars pick June anyway. Come with indoor options and a flexible order. The record: 22.7C days, 14.9C nights, 8.6 hours of sun and AQI 57.
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Nikko climate normals — September
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Nikko in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
Shoulder seasonschool holidays in 3 of the markets that fill it, an ordinary month(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Nikko's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Fair weatherNikko's weather peaks April–June, best around May.
Best weatherFair weatherToughest weather
What's on in Nikko in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Season
Wet season
MonsoonRisk23 rainy days and about 242 mm in the month — the real kind of rainy season, not afternoon showers.
from the climate normals
Nearby, and something's on
Within 300 km of Nikko — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Nikko?
Nikko in September — FAQ
- Is September a good time to visit Nikko?
- September in Nikko: warm, soaked, with clean air — fine if you can take 23 rainy days. It ranks #6 of 12 months for Nikko on SeasonMap's comfort score (70/100).
- What is the weather like in Nikko in September?
- In September, Nikko averages a daily high of 23.8°C and a low of 17.6°C, with about 241.5 mm of rain over roughly 23 rainy days.
- What is the air quality in Nikko in September?
- Nikko has a mean US Air Quality Index of about 38 in September.
Within 300 km: Hakuba's High trails and huts open around 1 Jul – 15 Oct, and Matsumoto's Kamikochi open season around 17 Apr – 15 Nov.