Nagano month by month: the valley and the mountains
Each note looks at two heights: the Nagano and Matsumoto basins, open all year, and the high mountains, which only open from mid-April to mid-November.
There is a valley in Nagano that keeps opening hours. Kamikochi, at about 1,500 metres in the Northern Alps, gets the year's first buses on 17 April and sees off the last ones on 15 November, at a closing ceremony held on the same day every year. Seven months pass between the two dates. For the other five, the valley is closed to the public, with no private cars in any season and no transport in winter.
Thirty kilometres to the east, as the crow flies, the Matsumoto basin never closes. It rains little there, the sun shines almost all year and life follows the rhythm of the orchards. That is Nagano Prefecture: a set of dry basins enclosed by ranges that keep the water and the snow for themselves. To understand it, choosing a season is not enough. You have to choose the moment when the two calendars cross.
01 Two calendars thirty kilometres apart
The Japan Meteorological Agency's reference values for 1991–2020 make it plain. Nagano city, at 418 metres, gets 965.1 millimetres of precipitation a year, a very low figure for Japan. Matsumoto, at 610 metres, adds up 1,045.1 millimetres and 2,134.7 hours of sun, more than the prefectural capital itself. These are leeward basins: the clouds coming from the sea unload first, on the mountains that surround them.
The Kamikochi station, at 1,510 metres, only measures rain, but that is enough: 2,721.3 millimetres a year, 2.6 times what falls on Matsumoto. Further north the same happens with snow. Nozawa Onsen, at 576 metres and about 35 kilometres from Nagano city, piles up 1,087 centimetres of snowfall a year; the capital, 163. Hakuba, at 703 metres, 655. Altitude explains part of it. The rest depends on which side of the mountain you are on.
Key moments at a glance
Kamikochi opens on the 17th with snow still on some paths; in the valleys, the cherries are finishing their bloom.
428.4 mm in Kamikochi: the wettest month in the high mountains.
Autumn comes down from 2,612 metres to the valley, the first snow falls above and apples are picked below.
A 199 cm snowpack in Nozawa; Nagano city, with 140 hours of sun.
02 April opens the door with the snow still inside
Spring reaches Nagano from below. In the city the average April high is already 17.4 degrees, and in Takato, in the Ina valley, the castle ruins park fills with some 1,500 cherry trees of the Takato kohigan variety, with small reddish flowers, declared a prefectural natural monument in 1960. They usually bloom in the first half of April.
Up high, the door opens at the same time, but what lies behind it is winter. The Tateyama Kurobe Alpine Route began its 2026 season on 15 April. Kamikochi opens on the 17th, and the local association's guide warns that in those first weeks some paths are still under snow and some facilities are closed. The season's opening ceremony, on 27 April, marks the point when the paths are usually clear and almost all the lodgings are running.
That lag is what April reveals: in the same week you can see cherries in bloom in the valley and snow on Kamikochi's paths. In the north, the contrast shows up at the Nozawa Onsen station, which still records a maximum average depth of 77 centimetres in April while Nagano city has no snow left. May completes the transition. It is the capital's sunniest month, with 214.8 hours, and one of its driest.
03 July, when the mountains keep the water
In the Kanto-Koshin region, to which Nagano belongs for Japanese weather purposes, the rainy season begins on average around 7 June and ends around 19 July. The basin feels it, but without drama: Nagano city gets 137.7 millimetres in July, its wettest month. In the mountains it is another story. Kamikochi records 286.5 millimetres in June and 428.4 in July, more than three times what Matsumoto gets that month.
Once the rains end, altitude becomes a refuge. In August the average high in Nagano city is 31.1 degrees; in Sugadaira, at 1,253 metres, it is 24.7, and the monthly mean there does not go above 19.5. This is the season when the prefecture climbs: to the plateaus, the huts and the trails that were covered in April. But it is also the season when the mountains look the same from June to September: green, open, with no visible sign that they have a closing date.
04 October: autumn comes down floor by floor
Autumn makes visible what summer hides: that the mountains have floors and each floor keeps its own clock. It starts at the top. At the Senjojiki cirque, in the Central Alps, the upper station of the Komagatake Ropeway sits at 2,612 metres, 950 above the lower one. According to the operator, from late September to early October the mountain ash turns red, the white birch yellow and the dwarf pine stays green. The first snow falls there around mid-October.
_08_Oct,_2012_-_panoramio.jpg?width=1200)
In the Northern Alps, the calendar published by the Kamikochi association follows the same descent. In the Karasawa cirque, below the Hotaka peaks, colour peaks in the last week of September in most years, and that is when the busiest period begins. In early October, colour on the slopes can already be seen from the valley floor, although down below it is still early. The maples peak in mid-month. The larches at the end, when their needles turn a warm yellow.
The result is a scene that only exists for a few weeks. The Komagatake Ropeway itself describes it this way: depending on when you go up, you may find snow on the summit, colour on the slope and green trees at the foot. In July the mountain is a single green block. In October it reads in layers, and each layer tells you how high you are.
In July the mountain is a single green block. In October it reads in layers, and each layer tells you how high you are.
05 Up high it closes, down below it is harvested
While the mountains get ready to close, the basins are at their best. Nagano is Japan's second apple-producing prefecture, after Aomori, and the harvest runs from late August to December, one variety after another. The Shinano Sweet, created in 1978 at the prefecture's fruit tree experiment station, has its main season in October and November. The Sun Fuji, the latest, comes in November and December.
The weather plays along. November is one of the driest months of the year in Nagano city, with 44.4 millimetres, and Matsumoto keeps 163 hours of sun, almost the same as in July. Up high, meanwhile, the season winds down. After the larches drop their needles in early November, Kamikochi's last week is quiet, with fewer buses and businesses already shut. On 15 November the last bus leaves. The Alpine Route holds out two more weeks, until the 30th.
06 After 15 November
When the high mountains close, winter is not shared out evenly. The snow piles up in the north of the prefecture, in the valleys facing the Sea of Japan. Nozawa Onsen gets 223 centimetres of snowfall in December, 366 in January and 282 in February, when it reaches a maximum average depth of 199 centimetres. That same February, Nagano city logs 140 hours of sun and Matsumoto 171. Nagano's winter is white in the mountain villages and bright and dry in the basins.
That snow opens another calendar, the ski season. In Hakuba, Happo-one's 2025-2026 season was planned from 1 December to 6 May; skiing ended on 19 April and the sightseeing lifts kept running until 6 May. In other words, when the skiing says goodbye, Kamikochi has already been open for two days. The two seasons of Nagano's mountains hand over to each other almost on the same day.
07 How to choose the month
If you want to understand Nagano, go in October. It is the month when the prefecture explains itself: you go up by ropeway and the colour is ahead of you, you come down to the valley and find it later, you return to the basin and the harvest greets you. The first half favours the summits, with Senjojiki and the first snow. The second half favours Kamikochi, with the maples and larches. Either lets you see the mountains before they close.
What you lose is just as clear. October is the busiest time in Kamikochi and Karasawa, mountain rainfall is still high, at 211.4 millimetres in Kamikochi, and the colour dates shift every year with the heat of the summer. If you want the high trails free of snow, late July, after the rains, and August are your window. If you want the spring lag, with cherries below and snow above, mid-April. And if what you are after is snow, January to February, but in the north, not in the basins.
The month to avoid is July before the rains end: it is when the mountains get the most water and when one floor is hardest to tell from another. And the date worth remembering is 15 November. After that day Nagano is still open, but only half of it.
