June is the start of summer in Japan. Average temperatures are high, and so are humidity levels, although not as intense as they'll become in July and August. Average highs across most of Honshu, Kyushu, and Shikoku sit in the high 70s and low 80s F (25-27° C), and overnight lows are not significantly lower. The humidity in many parts of the country, especially from Tokyo south, make the temperatures seems hotter. Sapporo, on the northern island of Hokkaido, is much cooler than other major cities, with an average June high of 70° F (21° C), but that may be a welcome break for many travelers.
The rainy season begins in the sub-tropical and tropical islands of Okinawa in May, but ends in late June. Hokkaido doesn't experience the rainy season, but most of the rest of Japan experiences increased rain from mid-June. It doesn't necessarily rain every day, but it's usually overcast and damp if not raining.
Crowds and Costs
June is low travel season in much of Japan, with the exception of the geographic extremes: Hokkaido and Okinawa. Many Japanese people travel to these destinations in June, either to escape the heat (Hokkaido) or to embrace it (Okinawa). Okinawa's peak season starts later in June, when the rain tends to clear. Transportation and accommodation costs are higher in these places than at most other times of year.
Elsewhere in Japan, the heat and humidity keep floods of visitors at bay, although it's not a bad time per se to travel in the more urban areas of Honshu, Shikoku, and Kyushu. Just be prepared with waterproof clothing or an umbrella, avoid lengthy outdoor activities (such as hiking), and plan to spend some time at indoor attractions like museums, palaces, and restaurants.
Where to Go
To retreat from the heat and humidity of more southern parts of Japan, Hokkaido is a great destination. Temperatures are generally warm without being hot, and not humid like southern parts of the country. Plus, one of Sapporo's major traditional festivals is held in June (see more below), drawing visitors.
At the other end of the country, Okinawa is a great place to go from late June, for beaches, summery weather, and cooling ocean swims. You'll discover a completely different side to Japan to the one generally promoted, of high-tech Tokyo and traditional Kyoto.
What to Do
While much of the country is a bit damp for pleasant hiking in June, if you want to get outdoors, the Japan Alps are a great place to go. These run down the center of Honshu, Japan's 'main' island, and the range is home to the highest mountains in Japan. Head to the Chubu Sangaku National Park, or hike the ancient Nakasendo Trail, which connects Kyoto and Tokyo.
If general city sightseeing is more your thing, conditions are generally alright for this in June. The temples and gardens of Kyoto are always charming, Tokyo's bustling neighborhoods can be enjoyed in any weather, and the fascinating (and infamous) cities of Hiroshima and Nagasaki pack a cultural and historic punch at any time of year.
Natsu Matsuri. Japanese summer festivals, or natsu matsuri, are held in many towns, cities, neighborhoods, and even small local streets throughout the country, all summer long. These usually include traditional dancing, music and costumes, portable shrines, large crowds, and plenty of food and drink.
Each festival has unique and distinctive characteristics. It would be impossible to list all of the festivals held in June that are worth checking out, but wherever you travel to you won't be too far from one that could be built into your itinerary. Ask your local specialist if this is something you're interested in experiencing.
Traveling to Japan in June? Check out these great itineraries
Hike Japan's Nakasendo Trail - 5 Days. Step back in time and immerse yourself in nature on this five-day hiking trip along the historic Nakasendo Trail. Feudal lords and samurai once walked this mountain path connecting Kyoto and Tokyo.
Explore Japan's Islands - 10 Days. Visit two of Japan's largest cities, Tokyo and Osaka, as well as some of the lesser-known islands surrounding the main island. Stargaze on Hachijojima, admire the volcano on Aogashima, and more.
Best of Old and New Japan: Tokyo, Kyoto, and More - 14 Days. The combination of historic and modern beauty makes Japan an ideal vacation destination. On this journey of old world-meets-new world, you will explore the progressive city of Tokyo, along with strolling through pockets of old Japan.