夏 SUMMER · JULY–SEPTEMBER · RARELY IN THE WATER
The season the park is famous for, without the thing it is famous for
At 24 to 25 °C mean air there is nothing to warm up against. The monkeys are there; the pool is mostly empty. What summer has instead is a valley with nobody in it and a trail you can walk at your own pace.
Mean air 21.0 to 25.4 °C in Nagano city, and the park at 850 m runs two to three degrees colder. The gate is 8:30–17:00.

One price in every month of the year, and the park asks visitors to arrive 30 minutes before closing time.
The ticket, in detail湯THE GUIDED DAY, YEAR-ROUND$136 (≈¥21,200)PER PERSON · $273 (≈¥42,600) FOR ONE · ¥800 (≈$5.1) AT THE GATEOne price in all twelve months. What changes is what is at the end of it.
Live dates in summerThe 3 months of summer, side by side
QUIETJuly and August are the same conditions with August adding the Japanese holiday traffic. September is the last quiet month before the park starts warning visitors off, and the coolest of the three.
What summer is, at this park
The quiet part of the year. The air is warm enough on its own, so the pool is mostly empty — wardens sometimes throw food in to bring the troop down at all, and the ones that get in are mostly the young, playing.
In the warm months the monkeys are rarely in the pool — the air is warm enough on its own; wardens sometimes throw food into the water to encourage them in, and the ones that do get in are mostly the young, playing.
The park publishes a predicted time for the monkeys coming down from the mountain and asks visitors to check before traveling and again on the day, through its live cameras and social accounts — the only thing that answers «will they be there today», and it is free.
Summer cannot be talked into a bathing monkey
Read before bookingWardens sometimes throw food into the water to bring the troop down at all, and the ones that get in are mostly the young, playing. No operator changes that, and the ones that show you a steaming pool in their photographs took it in February.
THE TROOP DECIDES Park staff work to attract the monkeys during opening hours, but the monkeys may not show up at all on certain days; appearances are particularly sporadic in autumn. Seven of the 21 tours on this site include the ¥800 (≈$5.1) gate fee in the price and the rest leave it at the gate; not one of them includes a monkey.
LIVE DATES · SUMMER · FROM NAGANO · ¥800 (≈$5.1) AT THE GATE
Summer, month by month
Of the 3 months in summer, September ranks highest on this site’s own order — 8th of twelve. That is a ranking, not a promise.
OR JULY · AUGUST · SEPTEMBER · ALL TWELVE COMPARED