24-Hour Room Service: Tschuggen Grand Hotel, Arosa, Switzerland

Alpine ski resorts that lack the year-round pull of an Eiger or Matterhorn often become ghost towns when the snow thaws, their hotels shuttered and all the ski instructors off to teach at surfing schools. But the threat posed by climate change to the future of low-lying resorts is forcing them to broaden their appeal and think of ways to attract visitors year-round.

One such resort is Arosa in the canton of Graubünden, where the flagship hotel, the Tschuggen Grand, has opened its doors for the summer season for the first time in almost 80 years. Since its establishment in 1929, the hotel has been dedicated to winter sports only.

So why is it changing the policy of a lifetime? Partly because more people are heading to the mountains for the excellent walking, riding and mountain-biking countryside surrounding Arosa, but also because of the sensational new spa created for the hotel by the Swiss architect Mario Botta.

The spa's four levels are lit from above by nine sail-shaped glass dormers, which create an extraordinary effect at dusk, silhouetted against the dark conifers surrounding the hotel. From the pool rise tapered spirals of pale Domodossola granite, while the granite-floored spa rooms are havens of maple-wooded calm, where guests can have thalassotherapy, Ayurvedic treatments and massage therapies by way of Thailand, Hawaii, Japan and China.

Imaginative lighting creates a different ambience after dark, when guests can soak in the heated outside pool and gaze at the stars over the Alps.

The spa blends well with the adjacent hotel, which was rebuilt in the Sixties after a fire, and given a major facelift in 2005. By successfully combining the warmth of Alpine rusticity and traditional materials with striking contemporary design, it has stolen a march on its more traditionally luxurious competitors elsewhere.

But sybarites need not restrict themselves to the spa. Guests can choose from three restaurants (a fourth, Bündnerstube, serves hearty rustic Swiss dishes only in winter). The more formal Grand Restaurant serves classic French dishes; La Vetta has refined Mediterranean cuisine such as scallops and ossetra caviar on pea confit with tomato ragout; while the simpler fare of La Provence is perfect for children.

LOCATION

Tschuggen Grand Hotel, Sonnenbergstrasse, Arosa, Graubünden, Switzerland (00 41 81 378 99 99; www.tschuggen.ch). The hotel is on high ground at the quieter, western end of Arosa, with views over forests and the ring of mountains that closes off the end of the valley. Car use is strongly discouraged for getting around, and there is a frequent free bus service along the valley, linking the station with hotels and cable cars for access to high-level summer walks or winter skiing. The hotel also has its own electric mountain railway, the Coaster, to whisk guests up the hill behind the spa.

Time from international airport: It's just under three hours by train from Zürich Airport station, changing at Chur for the enchanting narrow-gauge train journey up the Plessur valley to Arosa, where you can either be met by the hotel limousine or hop on the bus.

COMFORTABLE?

The input of designers is equally apparent in the bedrooms, with boldly coloured patchwork headboards – some damask, some striped, some chequered – that reach to the ceiling. Blocks of bright colour on the ceiling contrast with restful shades for the walls and fabrics. Large picture windows frame mountain vistas. There's enough storage space for a month's stay, and the bathrooms have generous-sized walk-in showers as well as baths. Smart loungers on the verandas are perfect for watching the sun disappear behind the mountains.

Freebies: Molton Brown toiletries, a board of Swiss cheese and sausage, and a fruit bowl in the bedroom.

Keeping in touch: Direct-dial phones, flat-screen TVs with satellite channels, and sockets for free broadband connection in rooms.

THE BOTTOM LINE

Doubles start at SFr415 (£205) including an elaborate buffet breakfast.

I'm not paying that: The sister four-star Sporthotel (00 41 81 378 63 63; www.valsana.ch) lacks the flair and panache of the Tschuggen, but guests can pay a supplement to use the spa. Doubles from SFr246 (£129) including breakfast.