Mont Terri Mountain
Geological ridge in Jura hosting rock laboratory
In the Swiss Jura, Mont Terri hosts a rock laboratory and a visitor centre studying Opalinus Clay; scientists, students and hikers use the trails and interpretive exhibits.
Mont Terri at a Glance#
About Mont Terri#
Mont Terri is a hill in the Jura Mountains in the Canton of Jura, Switzerland, notable as the location of an underground rock laboratory. The site hosts research dedicated to the properties of claystone and to questions around geological isolation of radioactive materials.
The main feature is the Mont Terri Rock Laboratory, an excavated facility with galleries and instrumentation where international teams run experiments on hydrogeology, geochemistry and rock mechanics. The facility is used for long-term experiments rather than general tourism, and it supports scientific collaboration on disposal concepts and engineered barriers.
The rock laboratory was developed to provide an in-situ research environment for studying the behaviour of clay formations under repository-relevant conditions. Over time it has become a reference site for experimental work on clay host rocks and underground research infrastructure.
Mont Terri sits in the Jura range near the France-Switzerland border in the Canton of Jura, occupying a geological setting typical of folded Jura terrain and clay-rich formations.
- Research focus: The site focuses on experiments in Opalinus Clay and related rock mechanics that are relevant to the long-term geological disposal of radioactive waste.
- Limited public access: Access to the underground laboratory is primarily for research personnel and organized visits; the facility supports international collaborative experiments.
What to See#
- Mont Terri Rock Laboratory: An underground experimental facility excavated in the local rock, used by international research teams to study claystone behaviour, hydrogeology and engineered-barrier interactions.
How to Get to Mont Terri#
The Mont Terri site is located near the Swiss-French border in the Jura region, north of St-Ursanne. Access to the laboratory is controlled and typically by arrangement; contact Nagra or the Mont Terri project for public visit schedules and directions. Regional roads connect to nearby towns with local transit options limited.
Tips for Visiting Mont Terri#
- The Mont Terri Rock Laboratory occasionally offers guided visits - book well in advance through the project's outreach office.
- Wear sturdy footwear for the geological trails; some paths are steep and loose.
- Combine a visit with the Jura countryside for cheese and watchmaking towns nearby.
Best Time to Visit Mont Terri#
Spring through autumn is best for visits and guided tours; check research-lab schedules for public outreach availability.
Weather & Climate near Mont Terri#
Mont Terri's climate is classified as Oceanic - Oceanic climate with mild summers (peaking in July) and freezing winters (coldest in January). Temperatures range from -3°C to 22°C. Abundant rainfall (1150 mm/year), wettest in June, distributed fairly evenly throughout the year.
| Month | Comfort | Temp | Feels | Rain | Sky | Humidity | Wind | UV | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | Poor | -3° - 3° | -4° | 87 mm | overcast | 92% | 3.4 m/s | 0.1 low | 8.8h |
| February | Poor | -3° - 4° | -3° | 86 mm | overcast | 89% | 3.3 m/s | 0.2 low | 10.1h |
| March | Poor | 0° - 8° | 1° | 79 mm | partly cloudy | 84% | 3.3 m/s | 0.5 moderate | 11.8h |
| April | Acceptable | 2° - 11° | 4° | 87 mm | partly cloudy | 79% | 3.0 m/s | 0.9 moderate | 13.5h |
| May | Acceptable | 6° - 16° | 11° | 112 mm | overcast | 79% | 2.8 m/s | 1.3 high | 14.9h |
| June | Good | 9° - 19° | 14° | 114 mm | partly cloudy | 77% | 2.7 m/s | 1.6 very high | 15.7h |
| July | Good | 11° - 22° | 16° | 99 mm | partly cloudy | 74% | 2.6 m/s | 1.6 very high | 15.3h |
| August | Good | 11° - 22° | 16° | 96 mm | partly cloudy | 75% | 2.4 m/s | 1.3 high | 14.1h |
| September | Good | 8° - 18° | 13° | 94 mm | partly cloudy | 78% | 2.5 m/s | 0.9 moderate | 12.4h |
| October | Acceptable | 5° - 13° | 7° | 93 mm | partly cloudy | 85% | 2.7 m/s | 0.4 low | 10.7h |
| November | Poor | 0° - 7° | 1° | 100 mm | overcast | 90% | 3.0 m/s | 0.2 low | 9.2h |
| December | Poor | -2° - 3° | -3° | 103 mm | overcast | 92% | 3.4 m/s | 0.1 low | 8.3h |