The weather is warm but not too hot in most parts of Japan in October. In the major cities of Honshu and Kyushu (Tokyo, Osaka, Kyoto, Fukuoka), average October highs remain in the low 70s F (low 20s C), but overnight lows drop to the high 50s (around 15° C), so you'll need a sweater.
Hokkaido is much cooler, and you can begin to see its extended winter creeping up, with highs in Sapporo of around 62° F (16° C), and lows of 45° F (7° C). Sub-tropical and tropical Okinawa remains hot, but not as hot as in the summer, with average October highs in Naha of 82° F (28° C), and lows of 73° F (23° C).
Rainfall is very low throughout the country in October, and average sunshine hours are high. So, if you prefer moderate temperatures and dry conditions (as many travelers do), October is a good time to travel in Japan.
Crowds and Costs
While foreign tourist numbers begin to pick up in October, this is not such a busy time for Japanese tourists, so many popular places won't be incredibly busy in October. Like during other busy times in Japan, book accommodation and transport as far in advance as possible to avoid disappointment, or having to pay higher prices than you'd like.
The exceptions are regions where autumn arrives a little earlier, such as Hokkaido, the Tohoku region of northern Honshu, and the higher elevations of the Japan Alps and other mountain towns elsewhere in Honshu. Japanese tourists love following the fall foliage, and anywhere where you can see this in October is likely to be busy.
Where to Go
There aren't really any 'bad' places to go in Japan in October. Whether you're more interested in cities and culture or nature and the outdoors, many places are worth heading to in Japan in October.
Keen hikers should head to Shikoku or the Japan Alps area of Honshu. Conditions are good in October for hiking, as temperatures are pleasant and conditions are dry. A great thing about doing multi-day hikes in Japan is that in many areas, these walking trails have been around for centuries, so there are inns and guesthouses to stay in along the way, for an ideal mix of nature and culture.
If you've always wanted to see one of Japan's most iconic attractions, Mt. Fuji, October is a good time to do so. The mountain is quite close to Tokyo, but it's not always visible because of the humidity in the air. Head to the Fuji Five Lakes (Fuji-go-ko) or Hakone areas for the best chances of views, as well as boat rides, gentle hikes, attractive temples, hot spring attractions, and more.
Kyoto is a highly popular destination, and for good reason—the modern city contains a huge number of old temples, shrines, and gardens, as well as traditional neighborhoods with old architecture. It'll be quite busy with foreign tourists in October, but conditions are good for wandering the bamboo groves and manicured gardens, so is a worthwhile destination regardless.
What to Do
As mentioned above, October is a great time to hike in Japan, whether on a multi-day trek (such as the Nakasendo Trail) or easier day hikes around Nikko, the Chichibu-Tama-Kai National Park, and more.
General sightseeing is a good option in October, because in many popular Japanese destinations you can combine indoor and outdoor activities. Check out fantastic museums and galleries, stroll through landscaped gardens and parks, take a river or harbor cruise, enjoy eating delicious—and regionally diverse—Japanese cuisine.
And, with cooler nights, October is also a great time to head to an onsen, a quintessentially Japanese experience. The Japanese have got hot spring bathing down to a fine art, and there are gorgeous bathing complexes all over the country. Some are indoors, others are burrowed into natural caves. They're available year-round, but are actually more comfortable when the weather's cool.
Traditional matsuri festivals. While many Japanese neighborhood festivals are held in mid-summer, there are some great options in October, too. The Matsue Suitoro in the western Honshu city of Matsue is a light and water festival centered around the city's castle. The Asama Onsen Taimatsu Matsuri is a fire festival held near Matsumoto (a worthwhile destination in its own right thanks to its beautiful castle and proximity to the northern Japan Alps). During the Kurama-no-hi Matsuri in the mountains near Kyoto, men carry burning torches through the village of Kurama while wearing loin cloths!
Traveling to Japan in October? Check out these great itineraries
Explore Japan: Tokyo, Kyoto, & Hiroshima - 14 Days. This trip takes you to the major cities of Tokyo, Kyoto, and Hiroshima, where you'll experience a mix of modern culture and timeworn traditions. You'll also venture to the temples and shrines in Nikko and a hot springs retreat in Hakone.
Self-Guided Walking Tour on the Nakasendo Trail - 10 Days. Take a walk through time on this self-guided tour of the Nakasendo Trail, part of feudal Japan's original network of highways.
Classic Highlights of Japan - 14 Days. On this two-week journey to the four corners of Honshu, you'll have plenty of time to enjoy its unmissable attractions. You'll visit sacred temples and shrines, go bike riding through the countryside, and roam around the capital's most famous neighborhoods.