With no doubts I would answer: whenever you can as every season might be the right one to visit Tuscany and Siena.
As soon as the days become longer and the temperature rises take an opportunity to visit Siena. Walk around the historic center, discover the 17 contrade (some of them have very interesting name), enjoy a caffe’ in one of the bar of the shell-shaped Piazza del Campo, enjoy a fantastic panoramic view of the city from the stands and the bastions of Medici Fortress. Also keep in mind that by mid May the roses will be blooming everywhere, even in the vineyards!
It is in summer that one of the most known event in town takes place: the famous Palio di Siena. It is an historic contest and you can see it twice a year in the Siena’s exquisitely beautiful main square, Piazza del Campo. It is not easy to get tickets, so plan well in advance to make sure to see the Palio of Madonna di Provenzano (July 2nd) or the Palio of Madonna Assunta (August 16th).
If you want to know more about the oldest horse race in the world, I would suggest to watch the documentary film directed by Cosima Spender and you will be initiated into the arcane world of the Palio, with its layers of intrigue, subterfuge, beauty and tradition.
Like Springtime, Autumn might be an excellent period for visiting the villages near Siena, getting lost and discovering Tuscany’s incredible landscape. The weather from September onwards is mild and it is the best moment to visit the natural thermal baths around Siena. If you are a food and wine lover well, you are in the right place as this is the best moment to organise an enogastronomico tour of the many vineyards and a taste of the glorious white truffle!
The colder months are a joy for photographers as the valleys and Tuscan hills are beautifully lit by the winter sun. If you are thinking that in the colder months there isn’t much to do in Siena, well think again as this this a good chance to visit museum, churches, historical buildings. For example, you should’t miss to visit Santa Maria della Scala and of course the restaurants and locande are the best place to warm up and boost your tatse-buds with typical food.