Mount Akagi
Volcano Volcanic mountain and caldera in Gunma Prefecture
Mount Akagi is a volcanic massif in Gunma Prefecture with caldera lakes such as Onuma-local hikers use forest trails, and winter sports take advantage of nearby slopes.
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Mount Akagi is a volcanic mountain complex in Gunma Prefecture, Japan, characterized by a broad caldera and a series of peaks surrounding crater lakes such as Lake Ōnuma. The mountain is a prominent natural feature north of the Kantō plain and is used for hiking, winter sports on lower slopes and seasonal recreation.
The volcanic complex was active in the geological past and now presents as a set of forested ridges and lakes within a caldera; trails and roads provide access to lakeside viewpoints and alpine ridges. The area is a regionally important scenic and recreational destination.
Mount Akagi lies northwest of the cities of Maebashi and Takasaki in central Gunma Prefecture, forming part of the inner volcanic arc north of the Tokyo metropolitan area.
- Volcanic caldera and lake: A dormant volcanic complex with a caldera that contains Lake Ōnuma, widely used for day hikes and scenic drives from nearby cities.
What to See #
- Lake Ōnuma: Ōnuma (Lake Onuma) is a caldera lake on the mountain's flank that is a popular scenic and recreational spot with trails and viewpoints.
- Volcanic summit complex: Several volcanic peaks and ridges form the complex summit area, with hiking routes linking summits and lakes within the caldera structure.
How to Get to Mount Akagi #
Mount Akagi is reached by bus or car from Takasaki and Maebashi; regional buses serve the lake areas and trailheads in season. Driving offers the greatest flexibility to reach higher trailheads.
Tips for Visiting Mount Akagi #
- Visit Lake Onuma in the lower slopes for peaceful views and shorter walks that are less crowded than summit routes.
- If attempting the ascent, check trailhead conditions and seasonal services in Gunma Prefecture.
- Combine with visits to Takasaki or Shibukawa for regional cultural sites.
Best Time to Visit Mount Akagi #
Late spring through autumn is best for walking and enjoying the lakes; winter requires winter equipment.
Weather & Climate near Mount Akagi #
Mount Akagi's climate is classified as Warm-Summer Continental - Warm-Summer Continental climate with mild summers (peaking in August) and freezing winters (coldest in February). Temperatures range from -8°C to 23°C. Abundant rainfall (1866 mm/year), wettest in August.
January
January is freezing with highs of 1°C and lows of -8°C. Moderate rainfall (54 mm).
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February
February is the coldest month with highs of 1°C and lows of -8°C. Moderate rainfall (70 mm) and partly cloudy skies.
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March
March is freezing with highs of 4°C and lows of -6°C. Regular rainfall (93 mm) and partly cloudy skies.
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April
April is cold with highs of 10°C and lows of 0°C. Significant rainfall (135 mm) and partly cloudy skies.
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May
May is cool with highs of 16°C and lows of 4°C. Significant rainfall (152 mm) and mostly overcast skies.
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June
June is cool with highs of 18°C and lows of 10°C. Heavy rain (224 mm) and mostly overcast skies.
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July
July is cool with highs of 22°C and lows of 14°C. Heavy rain (236 mm) and mostly overcast skies.
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August
August is the warmest month with highs of 23°C and lows of 15°C. The wettest month with heavy rain (322 mm) and mostly overcast skies.
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September
September is cool with highs of 19°C and lows of 12°C. Heavy rain (286 mm) and mostly overcast skies.
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October
October is cold with highs of 14°C and lows of 5°C. Significant rainfall (163 mm) and partly cloudy skies.
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November
November is cold with highs of 9°C and lows of 0°C. Regular rainfall (87 mm) and partly cloudy skies.
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December
December is freezing with highs of 4°C and lows of -5°C. Moderate rainfall (44 mm).
