France is a pretty big country and the weather varies depending on which region you travel to. By and large you'll enjoy temperate winters and mild summers, especially in the capital Paris. There are few finer things in life than relaxing on a cafe terrace during a cool summer night in Paris.
Backpacking along the Mediterranean you'll find that winters are far milder and summers are toasty hot, making it the perfect location to laze in the sun/in a yacht/in the back of a covertible sports car. Remember to bring your sun cream.
The northwest of France is cooler over the summer period. Along the Rhone Valley there's a strong north to northwesterly wind that's both bitterly cold and dry. If you're heading to this area of France on your gap year make sure you take a decent jacket.
If it's the winter snow you're after, head to the mountainous regions of the Alps, the Pyrenees, or Auvergne. Skiing season usually begins around the beginning of December, but it's always worth checking ahead to make sure enough snow has fallen.
If you're toward the north of France and in a rural area during the winter, there's a high chance you'll see a lot of snow. Be aware, as it can be very easy to get stuck in the middle of nowhere. Keep an eye on that forecast!