Kusatsu Weather: Snow, Temperatures & Seasonal Conditions for Visitors

Why Kusatsu's Weather Is Different from Lowland Gunma

Kusatsu Onsen (草津温泉) sits at approximately 1,200 meters (3,900 feet) above sea level, according to the official Kusatsu Onsen site. This elevation creates a microclimate dramatically different from the Gunma plains. While cities like Maebashi and Takasaki experience hot, humid summers and relatively mild winters, Kusatsu can be 10-15°C colder year-round.

The town is nestled in the mountains near the active Kusatsu-Shirane (草津白根山) volcano, which adds another dimension to local conditions — volcanic activity can affect trail access and occasionally produces gas alerts. Check Japan Meteorological Agency (JMA) alerts before planning any hiking near the volcano area.

For a broader look at weather patterns across the prefecture, see our Gunma weather overview. This article focuses specifically on Kusatsu's highland conditions and what they mean for onsen visitors, skiers, and outdoor enthusiasts.

Kusatsu Weather by Season

Winter (December-March): Heavy Snow and Subzero Nights

Winter is Kusatsu's defining season. According to JMA Amedas data, snowfall from December through March often exceeds 1 meter in depth. Temperatures range from approximately -10°C (14°F) on the coldest nights to around 5°C (41°F) during the day.

The heavy snowfall is what makes winter onsen bathing here so atmospheric — soaking in steaming hot spring water while snow falls around you is one of Kusatsu's signature experiences. However, the cold is genuine. Evenings and early mornings require serious layering, and walking between your ryokan and the public baths means brief exposure to freezing temperatures.

For visitors coming from Tokyo (where winter temperatures hover around 2-10°C), the temperature difference is significant. Kusatsu in January feels closer to northern Hokkaido than to the Kanto plains.

For details on how weather affects the onsen bathing experience specifically, see our Kusatsu onsen weather guide.

Spring and Autumn: Mild but Changeable

Spring (April-May) and autumn (September-November) bring comfortable daytime temperatures but can change quickly due to the elevation. Expect daytime highs in the 10-20°C (50-68°F) range, with nights dropping significantly cooler.

Spring snowmelt continues into April at this elevation, so early spring visitors may still encounter snowy or icy paths. Autumn foliage is typically spectacular in October, with the mountain setting adding vertical color gradients not visible in lowland areas.

Both shoulder seasons require layers. A sunny afternoon can feel warm, but clouds rolling in or the sun setting behind the mountains drops temperatures rapidly. For help timing your overall Gunma trip, see our guide on the best time to visit Gunma.

Summer (June-August): Cool Highland Escape

Summer temperatures at Kusatsu's 1,200m elevation rarely exceed 25°C (77°F), according to seasonal data. This is a dramatic contrast with lowland Gunma, where summer temperatures regularly surpass 35°C (95°F). The cool mountain air makes Kusatsu a popular summer escape for Japanese residents fleeing the heat.

June brings the tsuyu (梅雨) rainy season, with increased precipitation lasting through mid-July. Pack rain gear for this period. July and August are pleasant for hiking and outdoor exploration, though afternoon thunderstorms are common in mountain areas.

The cool evenings — dipping into the low teens Celsius even in August — make summer onsen bathing surprisingly enjoyable. Unlike lowland hot springs where summer heat makes bathing uncomfortably warm, Kusatsu's elevation keeps the experience pleasant year-round.

Snow Conditions and Skiing at Kusatsu Kokusai

Kusatsu Kokusai Ski Resort (草津国際スキー場) typically operates from late November through early May, according to the official ski resort site. Peak snow conditions run from January through February, when the snowpack is deepest and most consistent.

The resort's high-altitude location means it preserves powder snow longer than lower-elevation resorts in the region. Snow conditions are generally reliable throughout the season, though early November and late April may have limited coverage.

Detail	Information
Season	Late November - early May
Peak conditions	January - February
Lift hours	8:30-16:30 (varies by season)
Adult day pass	¥5,500 (~$37)
Children day pass	¥3,000 (~$20)
Advance booking	Recommended during peak snow season

Be aware that Kusatsu-Shirane volcanic activity can occasionally affect ski resort operations. The resort monitors JMA alerts and may close specific runs or the entire resort if volcanic risk levels rise. Check the official site before booking.

Driving to Kusatsu in Winter: Chains and Road Conditions

National Route 292 is the main road connecting lowland Gunma to Kusatsu Onsen. According to Gunma Prefecture road information, snow chains or studless winter tires are required on Route 292 from December 1 through March 31. Police checkpoints enforce this requirement — vehicles without proper winter equipment will be turned back.

The mountain road can experience sudden whiteout conditions, black ice, and significant snowdrifts during storms. If you are not experienced with winter mountain driving in Japan, consider taking the bus from Naganohara-Kusatsuguchi Station instead.

By public transport: From Tokyo Station, take the JR line to Naganohara-Kusatsuguchi Station (approximately 3 hours). From there, a bus runs to Kusatsu Onsen Bus Terminal in about 25 minutes (¥730 / ~$5). Buses operate year-round, though schedules may be reduced during heavy snowfall.

Many visitors on Reddit recommend taking public transport in winter specifically to avoid the stress and risk of mountain driving in snow conditions.

What to Pack for Kusatsu by Season

Season	Essentials
Winter (Dec-Mar)	Heavy insulated jacket, thermal layers, waterproof boots, gloves, hat. Crampons or ice grips for walking on icy streets.
Spring (Apr-May)	Warm layers, waterproof jacket. Paths may still be icy in early April.
Summer (Jun-Aug)	Light layers, rain jacket for tsuyu season. Evenings cool to 10-15°C.
Autumn (Sep-Nov)	Warm layers, waterproof outer layer. Temperatures drop quickly after sunset.

Regardless of season, pack for temperatures 10-15°C colder than what you would experience in Tokyo on the same day. The elevation effect catches many visitors off guard — particularly those arriving in spring or autumn expecting mild conditions.

High altitude also means stronger UV exposure year-round. Sunscreen is recommended even on cloudy winter days, as snow reflection amplifies UV levels at the ski resort.

Frequently Asked Questions

How much colder is Kusatsu Onsen compared to Tokyo in winter?

Kusatsu at 1,200m elevation is typically 10-15°C colder than lowland cities. Winter temperatures range from approximately -10°C to 5°C, while Tokyo stays around 2-10°C. The elevation creates conditions closer to northern Japan than the Kanto plains. Pack heavy winter gear including insulated jackets, waterproof boots, and thermal layers.

Do I need snow chains to drive to Kusatsu in winter?

Yes. Gunma Prefecture requires snow chains or studless winter tires on National Route 292 from December 1 to March 31. Checkpoints enforce this — vehicles without proper equipment are turned back. If you are not experienced with winter mountain driving, take the bus from Naganohara-Kusatsuguchi Station (25 minutes, ¥730).

When does ski season start and end at Kusatsu?

Kusatsu Kokusai Ski Resort typically operates from late November through early May, with peak snow conditions in January and February. Adult day lift tickets cost ¥5,500 (~$37). Advance booking is recommended during peak season. Check the official site for current season dates and any volcanic activity alerts.

Is summer a good time to visit Kusatsu Onsen?

Yes — summer is one of Kusatsu's most comfortable seasons. At 1,200m elevation, temperatures rarely exceed 25°C even in August, making it a popular escape from Tokyo and Gunma's 30°C+ lowland heat. Pack layers for cool evenings that drop into the low teens. June brings the rainy season, so rain gear is essential in early summer.