Gunma Weather Guide: What to Expect by Season and Region

Why Gunma Weather Varies So Much: Elevation Is Everything

Gunma Prefecture sits inland in the Kanto region, with no coastline to moderate temperatures. What makes its weather particularly tricky for trip planning is the elevation range: the capital Maebashi (前橋市) lies at roughly 100m above sea level, while Kusatsu Onsen (草津温泉) — one of Japan's most popular hot spring towns — sits at approximately 1,200m. That 1,100-meter difference creates two distinct climate zones within a single prefecture.

According to Japan Meteorological Agency data, Maebashi's annual average temperature is about 14°C, while Kusatsu averages roughly 7°C. In practical terms, this means you can leave Tokyo on a warm summer morning, arrive in Maebashi sweating through your shirt, then step off the bus in Kusatsu needing a jacket. Many visitors on Reddit and travel forums report being caught off guard by this gap — especially those arriving from Tokyo, where the weather bears little resemblance to Gunma's mountain towns.

The key planning insight: treat Gunma as two destinations when it comes to weather. What you pack and when you visit should depend entirely on whether you're heading to the lowland cities or the mountain onsen towns.

Lowlands vs Mountains: A Side-by-Side Comparison

This table shows the core weather differences between Gunma's two climate zones. For detailed Kusatsu weather conditions, see our dedicated guide.

Factor	Lowlands (Maebashi / Takasaki)	Mountains (Kusatsu / Minakami)
Elevation	~100m	~1,200m
Annual avg. temp	~14°C (57°F)	~7°C (45°F)
Summer highs (Aug)	~29°C (84°F)	~23°C (73°F)
Winter lows (Jan)	~-1°C (30°F)	~-10°C (14°F)
Annual snowfall	Trace / occasional	200–300cm (80–120in)
Rainy season impact	Heavy rain Jun–Jul	Rain + fog, less predictable
Snow season	Rare	November–April
Best for	Spring/autumn sightseeing	Summer escapes, winter skiing/onsen

The temperature difference between lowlands and mountains can exceed 15°C on summer days — enough to shift your experience from uncomfortably hot to pleasantly cool within a one-hour drive.

Season-by-Season Overview

For a month-by-month Gunma climate data breakdown, see our seasonal climate guide. Below is the high-level picture to help you choose when to visit and what conditions to expect.

Spring (March–May): Mild Lowlands, Lingering Mountain Snow

Lowland cities warm up quickly in spring, with cherry blossoms typically appearing in late March to early April. Daytime temperatures in Maebashi reach 15–20°C by April — comfortable for sightseeing in a light jacket.

The mountains tell a different story. Snow lingers at Kusatsu's elevation well into April, and some mountain roads remain closed until late April or early May. If you're planning a spring onsen trip, check road conditions before driving. The ski season at nearby resorts typically ends in late March, though conditions vary year to year.

Spring is one of the most comfortable times to combine lowland and mountain visits — just bring layers for the elevation change.

Summer (June–August): Hot Plains, Cool Highlands

Gunma's lowlands get hot. Maebashi regularly hits 29°C+ in August with high humidity, and the city has no sea breeze for relief. The rainy season (tsuyu) runs from early June through mid-July, bringing persistent rain and muggy conditions.

The mountains, however, function as a natural escape. Kusatsu averages 23°C in August — cooler than most of Japan's popular destinations. This makes summer the prime season for highland onsen visits. Pack rain gear regardless of your destination; summer thunderstorms hit both zones, though mountain weather is less predictable.

For best time to visit Gunma by activity, including hiking and festival timing, see our dedicated guide.

Autumn (September–November): Foliage and Comfortable Temperatures

Autumn is arguably Gunma's most pleasant season for travel. Lowland temperatures settle into the 15–22°C range in October, and the mountains begin their foliage display earlier than the plains — typically mid-October at Kusatsu's elevation versus late October to early November in Maebashi.

This staggered foliage season means you can time visits to catch peak color at different elevations. Early autumn (September) still carries summer's warmth in the lowlands but feels crisp in the mountains. By late November, mountain towns approach winter conditions — the first snowfall at Kusatsu often arrives in October or November, well before the lowlands see any snow.

Winter (December–February): Snow in the Mountains, Dry in the Cities

Gunma's winter splits sharply by elevation. Lowland cities like Maebashi and Takasaki (高崎) are cold but relatively dry, with temperatures hovering around 0–8°C and only occasional light snow that rarely accumulates.

The mountains transform entirely. According to the Kusatsu Onsen Tourism Association, Kusatsu receives 200 to 300cm of annual snowfall, with the heaviest accumulation from January through March. Roads to mountain onsen towns can close temporarily during heavy storms, and driving requires winter tires or chains — no exceptions.

Winter is peak season for skiing at resorts like Kusatsu Kokusai and Manza, and there's something undeniably appealing about soaking in an outdoor onsen (rotenburo / 露天風呂) surrounded by snow. For Kusatsu snow and seasonal conditions, including road closure updates, see our detailed guide.

What to Pack for Gunma

Your packing list depends entirely on which zone you're visiting — and ideally, you should prepare for both.

Lowland cities (Maebashi, Takasaki):

Season	Essentials
Spring	Light jacket, umbrella
Summer	Breathable clothing, sunscreen, rain gear
Autumn	Medium layers, light sweater
Winter	Warm coat, gloves (snow gear unnecessary)

Mountain towns (Kusatsu, Minakami):

Season	Essentials
Spring	Warm layers, waterproof jacket (snow possible through April)
Summer	Light layers + a fleece or jacket for evenings
Autumn	Warm jacket, hat, gloves by late October
Winter	Heavy winter coat, thermal base layers, waterproof boots, snow gear

The single most common mistake travelers make: packing for the lowlands and freezing in the mountains. Even in summer, mountain evenings drop below 15°C. Bring at least one warm layer regardless of when you visit.

Weather-Related Travel Tips

• Check elevation before booking: Your hotel's elevation matters more than the prefecture-level forecast. A "Gunma weather" search gives you Maebashi data, which is useless for Kusatsu planning.
• Mountain road closures: Winter roads to Kusatsu and other mountain towns can close with little notice during heavy snow. Check prefectural road information before driving between November and April.
• Winter tires are mandatory: Rental car companies in the region typically provide winter tires automatically from November through March, but confirm when booking. Chains may be required on top of winter tires during storms.
• Train access in winter: The JR Azuma Line (吾妻線) to Naganohara-Kusatsuguchi Station runs year-round, but connecting buses to Kusatsu (60 minutes, approximately ¥1,500) may run reduced schedules in heavy snow.
• Summer humidity: Lowland Gunma is among the hottest areas in Kanto. If heat is a concern, prioritize mountain destinations between June and September.
• Microclimates: A one-hour drive uphill can mean a 10°C temperature drop. If you're day-tripping between zones, dress in removable layers.

Frequently Asked Questions

How much colder is Kusatsu than Maebashi in Gunma?

The annual average temperature difference is about 7°C — Maebashi averages 14°C while Kusatsu averages 7°C. In summer, the gap widens: Kusatsu can be 15°C or more cooler than Maebashi on the same day, thanks to the 1,100-meter elevation difference between the two towns.

Does it snow in Gunma's lowland cities?

Rarely and lightly. Maebashi and Takasaki occasionally see light snow in winter, but significant accumulation is uncommon. Mountain towns are a different story — Kusatsu receives 200 to 300cm of snowfall annually, with heavy accumulation from January through March.

When is the best time to visit Gunma?

It depends on what you're after. Spring (April–May) and autumn (October–November) offer the most comfortable temperatures for general sightseeing across both zones. Summer is ideal for escaping to cool highland onsen towns. Winter is peak season for skiing and snowy onsen experiences. For a full activity-by-season breakdown, see our best time to visit Gunma guide.

Do I need winter tires for driving in Gunma?

For mountain areas like Kusatsu and Minakami from November through March, winter tires are mandatory — roads can be icy and snow-packed. Lowland city driving rarely requires them. Most rental car companies in the region equip vehicles with winter tires automatically during the snow season, but always confirm at pickup.