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 at a Glance#
Address: Lac de Mauvoisin (Barrage de Mauvoisin), Valais, Switzerland - accessed from the village of Fionnay
Admission: Free to view; access roads and some facilities may charge for parking
About Lac de Mauvoisin#
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.
| Month | Comfort | Temp | Feels | Rain | Sky | Humidity | Wind | UV | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | Poor | -9° - -2° | -10° | 122 mm | partly cloudy | 84% | 3.3 m/s | 0.2 low | 9.0h |
| February | Poor | -9° - -2° | -10° | 124 mm | partly cloudy | 84% | 3.5 m/s | 0.3 low | 10.2h |
| March | Poor | -7° - 0° | -8° | 111 mm | partly cloudy | 87% | 3.7 m/s | 0.6 moderate | 11.8h |
| April | Poor | -4° - 3° | -5° | 112 mm | overcast | 83% | 3.6 m/s | 1.0 high | 13.4h |
| May | Poor | 0° - 8° | 1° | 118 mm | overcast | 78% | 3.5 m/s | 1.4 high | 14.7h |
| June | Acceptable | 3° - 11° | 5° | 103 mm | partly cloudy | 75% | 3.4 m/s | 1.8 very high | 15.4h |
| July | Good | 6° - 15° | 10° | 86 mm | partly cloudy | 75% | 3.3 m/s | 1.9 very high | 15.1h |
| August | Good | 6° - 15° | 11° | 96 mm | partly cloudy | 75% | 3.1 m/s | 1.6 very high | 13.9h |
| September | Good | 4° - 12° | 6° | 89 mm | partly cloudy | 78% | 3.2 m/s | 1.0 high | 12.4h |
| October | Poor | 1° - 7° | 1° | 126 mm | partly cloudy | 80% | 3.2 m/s | 0.5 moderate | 10.8h |
| November | Poor | -4° - 2° | -5° | 135 mm | partly cloudy | 85% | 3.5 m/s | 0.2 low | 9.4h |
| December | Poor | -7° - -1° | -9° | 132 mm | partly cloudy | 83% | 3.5 m/s | 0.1 low | 8.6h |
