Lac de Mauvoisin
Monastery Large Swiss reservoir notable for massive arch dam
Glacial reservoir behind the Mauvoisin Dam in Valais, noted for a large concrete dam and glacier‑fed waters; hikers and climbers use nearby trails and refuge access into high alpine terrain.
Lac de Mauvoisin is a reservoir in the canton of Valais created by a large dam in the Mauvoisin valley. The lake serves as a storage basin for hydroelectric generation and is set amid high alpine peaks and glaciers.
Trailheads around the reservoir lead to alpine hikes and glacier viewpoints, and the dam itself is a focal point for many visitors who come to view the engineering in a mountain setting. Recreational use is primarily hiking and photography rather than swimming.
The reservoir was formed when the valley was impounded by dam engineering, converting a mountain valley into a regulated storage lake for electricity and water management. Over time access infrastructure and paths were developed for maintenance and for visitors.
It lies in the upper Val de Bagnes in Valais, surrounded by steep summits and glacial cirques and reachable from valley villages that serve as access points.
- Hydropower: Forms behind a major concrete dam and is used for hydroelectric power, with stark dam walls and high mountain scenery as viewing points.
How to Get to Lac de Mauvoisin #
Drive from Martigny or Sion toward the Val de Bagnes, following signs to Fionnay and the Mauvoisin dam. Mountain roads lead to parking close to the dam; summer access best.
Tips for Visiting Lac de Mauvoisin #
- Walk the dam crest early in the day for clear views of the reservoir's turquoise expanse.
- Combine the visit with a hike into surrounding peaks; many trails start near the dam parking.
- Bring windproof layers - the high valley can be exposed even in summer.
Best Time to Visit Lac de Mauvoisin #
Summer and early autumn are the best windows for access and hiking; winter access is limited.
Weather & Climate near Lac de Mauvoisin #
Lac de Mauvoisin's climate is classified as Subarctic - Subarctic climate with cool summers (peaking in August) and freezing winters (coldest in January). Temperatures range from -9°C to 15°C. Abundant rainfall (1354 mm/year), wettest in November, distributed fairly evenly throughout the year.
January
January is the coldest month with highs of -2°C and lows of -9°C. Significant rainfall (122 mm) and partly cloudy skies.
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February
February is freezing with highs of -2°C and lows of -8°C. Significant rainfall (124 mm) and partly cloudy skies.
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March
March is freezing with highs of 0°C and lows of -7°C. Significant rainfall (111 mm) and partly cloudy skies.
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April
April is freezing with highs of 2°C and lows of -4°C. Significant rainfall (112 mm) and mostly overcast skies.
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May
May is cold with highs of 8°C and lows of 0°C. Significant rainfall (118 mm) and mostly overcast skies.
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June
June is cold with highs of 11°C and lows of 3°C. Significant rainfall (103 mm) and partly cloudy skies.
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July
July is cool with highs of 15°C and lows of 6°C. Regular rainfall (86 mm) and partly cloudy skies.
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August
August is cool with highs of 15°C and lows of 6°C. Regular rainfall (96 mm) and partly cloudy skies.
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September
September is cold with highs of 12°C and lows of 4°C. Regular rainfall (89 mm) and partly cloudy skies.
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October
October is cold with highs of 7°C and lows of 0°C. Significant rainfall (126 mm) and partly cloudy skies.
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November
November is freezing with highs of 2°C and lows of -4°C. The wettest month with heavy rain (135 mm) and partly cloudy skies.
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December
December is freezing with highs of -1°C and lows of -7°C. Significant rainfall (132 mm) and partly cloudy skies.
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