If you’re planning a summer trip to Hakone, expect warm days, cooler nights, and a nice escape from Tokyo’s muggy heat. Average summer temperatures usually land in the low 70s to low 80s °F (about 22–28°C), so it’s pretty comfortable for sightseeing, hiking, or even soaking in a hot spring.
You’ll notice June tends to be rainier, and July and August get warmer and more humid. Even with the rain, the lush greenery and seasonal flowers—especially hydrangeas—make Hakone’s mountains, lakes, and gardens feel extra special.
Hakone’s elevation shifts a lot, so the weather can change depending on where you are. Down in places like Hakone Yumoto, it feels hotter and closer to Tokyo’s climate. Up higher, it stays cooler and breezier. This variety gives you options, whether you want to dodge the heat or jump into the lively summer festivals.
Overview of Hakone’s Summer Climate
Hakone’s summer brings warm days, frequent rainfall, and high humidity. The mountains help keep temperatures lower than Tokyo, but the air can get heavy with moisture. Nights cool off, greenery thrives, and the climate feels shaped by both altitude and the seasonal monsoon.
Temperature Ranges and Seasonal Patterns
From June to September, daytime temperatures in Hakone usually sit between 19°C (66°F) and 27°C (81°F). July and August are the warmest, with highs averaging around 23–24°C (73–75°F).
At night, temperatures drop to about 17–21°C (63–70°F), making it easier to sleep than in the lowlands.
Rain plays a big part in Hakone’s summer. June kicks off the rainy season, and precipitation often tops 240 mm (9.5 in). September usually brings the most rain, with close to 278 mm (11 in).
You’ll notice a rhythm: June is wet and mild, July and August are warmer and still damp, and September brings heavy rain with slightly cooler days. This pattern keeps Hakone’s dense forests and flowers looking vibrant.
Humidity and Comfort Levels
Humidity stays high all summer, hovering around 80–87%. The air feels warmer than the numbers say. Even on cooler days, all that moisture can make things feel sticky, especially if you’re out hiking.
Altitude and cloud cover help take the edge off the heat. Unlike sea-level cities, Hakone rarely gets above 30°C (86°F). Still, the dampness means you’ll want to be ready for sudden showers, so light rain gear is a must.
Evenings are the most comfortable, with cooler temps and breezes drifting through the valleys. While days can get muggy, those cooler nights make outdoor dining or a dip in an onsen way more enjoyable.
Comparison With Tokyo’s Summer Weather
Tokyo’s summer feels hotter and more stifling than Hakone’s. In August, Tokyo often hits 30–33°C (86–91°F), but Hakone averages closer to 24°C (75°F).
Nights in Tokyo might not drop below 25°C (77°F), while Hakone cools off several degrees, so it’s easier to rest.
Both places are humid, but Hakone’s altitude gives it the edge. The mountain air, though still damp, feels fresher than Tokyo’s thick urban atmosphere.
If you’re looking to escape Tokyo’s heat, Hakone offers a real drop in temperature, more greenery, and plenty of shade. Rain happens often, but the cooler air makes summer outings much more bearable than in the city.
Monthly Breakdown: June, July, and August
Hakone’s summer means steady warmth, high humidity, and frequent rain. Temps rise from mild in June to their peak in August. July is the turning point into the hottest part of the season. Altitude and rainfall patterns really shape how you’ll experience the weather.
Typical Weather in June
June starts summer off gently in Hakone. Highs reach about 22–23°C (72–73°F), and lows stay near 17°C (62°F). The air feels pleasant, but humidity climbs as the rainy season kicks in.
Rain is common, with showers popping up many days. You’ll want to carry light rain gear since the afternoons can get especially damp.
Long daylight hours give you more time to explore. Even with the rain, the cooler air at higher elevations makes it manageable to get outside. Lower spots like Hakone Yumoto feel warmer and more humid.
Key points for June:
- Highs: ~22–23°C (72–73°F)
- Frequent rain, especially mid to late month
- Good for hiking if you’re ready for wet weather
Typical Weather in July
July heats up. Highs reach about 26–27°C (79–81°F), and lows hover around 20–21°C (69–70°F). It’s humid, and rain stays frequent, making July one of the wettest months.
Showers can be heavy, but they usually don’t last long. The rain brings out lush greenery, which is great if you love nature. Trails can get slippery, so bring decent shoes.
You’ll still get plenty of warm, clear days in July. The heat and humidity make lower areas feel warmer, so you might find some relief up by Lake Ashi or on the slopes.
Key points for July:
- Highs: ~26–27°C (79–81°F)
- One of the rainiest months
- Hot and humid, but cooler at higher spots
Typical Weather in August
August tops the charts for heat in Hakone. Highs climb to about 28°C (82–83°F), and lows stick around 22°C (72°F). The heat index can feel closer to the low 30s °C (around 90°F), especially in the valleys.
Rainfall drops off a bit from July, but humidity stays high. Short thunderstorms can roll through, though you’ll see more dry, hot days now.
It’s best to get outside in the morning or evening, when it’s cooler. Higher elevations are more comfortable, so mountain viewpoints and shaded forests get popular.
Key points for August:
- Highs: ~28°C (82–83°F)
- Hottest month
- Humid, with fewer rainy days than July
Rainfall, Sunshine, and Cloud Cover
Hakone’s summer weather brings warmth, plenty of rain, shifting clouds, and moderate sunshine. You’ll get a mix of wet days and clearer spells, and the weather can change fast thanks to all those mountains.
Average Rainfall and Rainy Days
Rain peaks in Hakone during July and August. July sees about 183 mm (7.2 in) of rain over roughly 20 days. August has a bit less, but showers are still common. September can be even wetter, averaging over 270 mm (10.6 in) across nearly 19 days.
Rain usually shows up as steady showers or quick, heavy downpours. Because Hakone is so mountainous, rainfall can really differ by elevation. Lower valleys might get lighter showers, while higher slopes often see heavier, longer rain.
If you’re planning to be outdoors, expect interruptions and bring waterproof gear. Trails get slippery, and fog often rolls in after rain, making it harder to see.
Sunshine Hours and Daylight Length
Summer in Hakone means long daylight hours. In June, you’ll get around 14 to 15 hours of daylight. July and August average closer to 13 to 14 hours. That gives you plenty of time to get out, even if some of it’s cloudy or rainy.
Even with the long days, actual sunshine is limited by clouds. On average, Hakone gets 4 to 5 hours of direct sunshine per day in summer. Mornings can start bright, but clouds or rain often move in later.
With all that daylight and changeable sunshine, it’s easier to keep your plans flexible. Early mornings usually have the clearest skies, which is great for views of Mount Fuji or getting outdoors before the crowds.
Cloud Cover Trends During Summer
Clouds are a summer staple in Hakone, with skies often partly cloudy to mostly overcast. In June, about 60% of days are cloudy. July and August drop a bit, closer to 50–55%.
Warm, humid air helps clouds form, especially in the afternoons. You’ll probably notice clearer mornings, then thicker clouds building up as the day goes on. That’s just how it goes in the mountains.
Clouds can limit sunshine, but they help keep temperatures down compared to lowland cities. Even on overcast days, it’s still warm and humid. Light rain gear is smart to have, since clouds often mean showers are coming.
Wind Speed and Other Weather Factors
Summer in Hakone means mild to moderate winds, high humidity, and plenty of rain. These factors all shape how comfortable you’ll feel outside and can change your plans for hiking, sightseeing, or relaxing in an onsen.
Average Wind Speed in Summer
Wind in Hakone isn’t too wild in summer. Average speeds usually stay below 7 miles per hour, so you won’t get blasted by gusts while you’re out and about.
The mountains block most of the strong wind, but you’ll still catch breezes around open valleys or lakes. These lighter winds give some relief from the muggy air, especially in July and August when it really heats up.
If you’re hitting walking trails near Lake Ashi or checking out viewpoints, the gentle winds make things more pleasant. Hakone doesn’t usually get typhoon-level winds in summer, but a quick storm can still bring a short burst of gusts.
| Month | Avg. Wind Speed | Conditions |
|---|---|---|
| June | ~6.5 mph | Light breeze, occasional rain |
| July | ~6.0 mph | Calm, humid |
| August | ~6.2 mph | Warm, muggy, occasional gusts |
Relative Humidity and Air Quality
Humidity really shapes summer in Hakone. From late June to mid-September, high dew points make the air feel heavy and damp. This is most obvious during the rainy season in June and July.
Relative humidity levels often stay above 70%. It can feel uncomfortable, but the mountain air, compared to Tokyo, helps take the edge off. Even when it’s sticky, nights cool down enough to give you some relief.
Air quality in Hakone is usually good because it’s higher up and far from big cities. The forests filter out pollutants, so smog or haze isn’t much of an issue. Mist and low clouds are common though, which can cut down visibility on mountain trails and at scenic spots.
For comfort, wear light clothes that dry fast and keep hydrated. If you’re sensitive to humidity, plan your activities for morning or evening to dodge the stickiest heat.
Regional Variations in Hakone
Hakone’s summer weather isn’t the same everywhere. Elevation and local geography create real differences in temperature, rain, and cloud cover across the region. These changes can affect how comfortable you feel and what activities make the most sense in each area.
Weather Differences by Elevation
Hakone sits in the mountains, with elevations from low valleys to peaks over 1,000 meters. Higher up, it stays cooler in summer—often by 3–5°C compared to low areas like Hakone Yumoto. Hot days feel better in the mountains, but you’ll see more clouds and fog.
Down near the train stations, afternoons get warmer and humidity spikes. Rain can feel heavier here, since storms gather in the valleys. On the upper slopes, it’s less humid but the weather changes fast, with sudden showers or mist rolling in.
If you’re planning to hike, remember that trails higher up can feel chilly even in August. Packing a light jacket isn’t a bad idea, especially for evenings when temps drop quickly.
Microclimates in Sengokuhara, Gora, and Lake Ashi
Hakone’s different areas each have their own microclimates. Sengokuhara, with its broad plateau, usually stays drier than the rest.
Summers here don’t feel as humid, and breezes sweep across the grasslands. Walking or cycling feels pretty nice, honestly.
Gora sits on a slope, so you’ll notice warmer days, but afternoon showers pop up often. The gardens here really soak up the warmth and rain, so flowers and greenery just explode in summer.
Lake Ashi feels cooler thanks to its higher elevation and all those forests. The lake itself tends to create a lot of morning fog, especially in early summer.
By midday, though, things usually clear up, and you get comfortable weather for sightseeing cruises or just wandering by the water.
It’s honestly wild how you can get such different summer weather just by traveling a short distance in Hakone.
Summer Events, Flowers, and Local Experiences
Hakone’s summer packs in cultural festivals, blooming flowers, and those classic hot spring visits. You can jump into lively community celebrations, take in bursts of color from the blooms, and unwind in an onsen, all while finding ways to keep cool.
Seasonal Festivals and Outdoor Activities
Hakone’s local festivals bring together music, food, and tradition. In July and August, fireworks light up the sky above Lake Ashi, and the reflections on the water look amazing.
Food stalls pop up with yakitori, noodles, and sweet treats, which makes the whole event feel even more festive.
Hiking trails get a lot of love in summer. The higher elevations around Mount Hakone give you cooler air, so hiking feels easier than it does in Tokyo.
Trails near Lake Ashi and through the forests offer up views of both the lake and Mount Fuji if you catch a clear day.
Boating on Lake Ashi is a solid choice too. You can hop on a sightseeing cruise or rent a paddle boat and just drift for a while.
These outdoor activities mix well with summer festivals, so you’re never short on things to do.
Hydrangeas, Lilies, and Cherry Blossoms
Summer flowers really brighten up Hakone. Hydrangeas start blooming in June, and they basically cover the hillsides and even the railway tracks in blue, purple, and pink.
The Hakone Tozan Railway gets famous for these views, and trains slow down so you can actually enjoy the blossoms.
By July, lilies are everywhere in Sengokuhara. The Sengokuhara Lily Garden shows off thousands of plants across open fields.
Walking paths wind through the flowers, and the cooler mountain air definitely helps make the visit more enjoyable.
While cherry blossoms are mostly for spring, you might spot some late-blooming types at higher spots in early summer.
They’re not as common, but if you find them, it’s a quieter way to catch the blossoms without the big crowds.
Onsen Visits During Summer
Hakone’s pretty well-known for its onsen, and honestly, summer can still be a great time to check them out. Lots of ryokan and public baths have outdoor pools, so you can kick back and soak in the hot water while taking in the mountain views and breathing in fresh air.
Some onsen even set up shaded spots or build their baths right next to rivers, which brings in a natural coolness. That little breeze or the sound of water makes things way more comfortable, even if the weather’s on the warmer side.
People really love evening visits in summer. Once the sun goes down, the air feels cooler, and sitting in a hot spring under the night sky just feels peaceful.
Whether you’re hanging out in Hakone Yumoto or closer to Sengokuhara, you’ll spot plenty of places that mix relaxation with the best of the season’s scenery.