Lyon is France's culinary center, located in the Rhône Valley.
Lyon offers cold and dry winters. Summers are wetter, but rainfall isn't predominant any time during the year.
Spring and fall are the best times to go to Lyon, although you'll likely encounter some rain. Summers can be hot and muggy. September is still quite warm, and you'll avoid some of the summer traverers, although Lyon isn't as heavily touristed as some cities in France.
Winters are cold and damp--Lyon is subject to heavy fog and mist December through February as the damp gets caght in the Rhône Valley. But then again, Lyon's cuisine offers some warming dishes that can make you feel better in a jiff.
The charts below show the historic high and low temperatures and average monthly rainfall for Lyon.
Le Loft des Augustins by Mon Hotel Particulier (apartment)