Short autumn breaks in Italy can be delightful – but also risky. There are days in late October when you can swim in the sea off Capri and it feels like August. At other times, though, rain and plunging temperatures can ruin a much-anticipated long weekend. Cultural city breaks are one safe option – but for those determined to extend summer towards Christmas and get in an al fresco swim, there is another option: hot springs.

Tuscany is easily the best Italian region for those wanting to get into hot water out of season. However, you need to exercise a little caution, as thermal springs – or ‘le terme’ – are still associated with medical treatments in Italy, and many are not even hot. Staid, cold spring resorts like Montecatini or Chianciano Terme – ‘Italy’s liver-cure capital’, as the sign at the town’s entrance proudly proclaims – revolve around gentle walks in terribly neat, terribly dull parks and the sipping of water with supposedly restorative properties.

The hot spring resorts too have serious curative packages should you need them, and spa doctors are on hand for consultations. But, these days, they’re also awake to the sheer hedonistic pleasures of wallowing in hot water on days when only Finns, Russians and masochists would consider swimming in an unheated pool.

Tuscan hot springs fall into two main categories: free, no-frills countryside dips and the full-on spa resort experience.

Don’t dismiss the first option. One of my most memorable thermal experiences was sipping champagne one New Year’s Eve, many years ago, in the Cascate del Mulino of Saturnia, south of Grosseto – a free-for-all site where natural hot water (at a very pleasant 37°C) cascades down a white clay slope in which a series of basins have been excavated. You park your car, shimmy into that swimming costume, choose your basin – and come out stinking of sulphur. Sometimes we would drive up here from Rome for an early evening swim and stop off in a nearby trattoria on the way back. The owner had a special dining room for Cascate returnees – far away from other guests.

Other democratic Tuscan hot spring experiences include three rustic basins below the postcard-pretty town of San Casciano dei Bagni, south-east of Siena, where the town’s intelligentsia wallows alongside local farmers and their scooter- driving sons and daughters. There’s no room to swim properly in most of the free thermal springs, but if you like the idea of a hot open-air bath with a group of friends and a few strangers in picturesque surroundings, they certainly deliver.

One of the best of the proper resorts is also in San Casciano dei Bagni. Reopened in 2004 after a renovation, Fonteverde (www.fonteverdespa.com) was originally built by a Medici grand duke in the 17th century, and the resort’s impressive main palazzo dates from that era. A full range of treatments is available, from classic massages, to a Bioaquam circuit with pummeling hydromassage jets and a large outside therapeutic pool, which is the best of the hotel’s seven pools for those who just want to swim. Rooms and food are in the luxury bracket – but so are prices. Keep an eye out for packages, though, like the Spa & Lunch Wellness break – from €604 for two for two nights, with access to pools, plus breakfast and lunch. It’s not a bad idea to be left free for dinner, as there are great country restaurants nearby.)

In Saturnia, if the hippie thing in the Cascate is not for you, head for Terme di Saturnia (www.termedisaturnia.it) – a Leading Hotels resort just outside the village. They take their treatments seriously here but, to compete with the Asian-style sensorial spa, have recently launched the more leisure-oriented Blackrose spa-within- a-spa, which has a pampering focus … gold-leaf facial, anyone? With its 18-hole, par-72 course, this is also the best of the region’s spa resorts for golfers.

But my favourite Tuscan spa town has to be Bagno Vignoni. A tiny Renaissance village, its main square is taken up by a walled pool of hot water that feaured in Andrei Tarkovsky’s film Nostalgia. It’s off limits to bathers these days, but you can swim in the scenic pool of the charmingly old-fashioned Posta Marcucci hotel (www.hotelpostamarcucci.it), or in the squeaky new Adler Thermae resort (www.adler-thermae.com) with its huge pool overlooking the olive-clad hills and walled towns of this rugged area of southern Tuscany.

And bear in mind that all of these hotels or resorts also cater for day visitors who just want a swim – allowing you to combine a cultural break in Siena or Montepulciano with a delicously unseasonal open-air splash.