The best time to run the GR20 is from late June to early September.
Stretching from Conca in the south to Calenza in the north, this remarkable long distance trail follows the backbone of the mountains that divide the island of Corsica. Often billed as one of the toughest long distance trails in Europe, the route is definitely challenging but has plenty of unforgettable rewards along the way--not least the stunning scenery as you wind up, down and through the heart of this Mediterranean island.
Need to Know
The path is marked with red and white rectangle blazes. The huts and shelters along the route are only maintained from June to the end of September, and you need to book your stay in advance during the busy season.
Depending on how you choose to tackle the trail, most runners are looking at a 10-15 day outing to run the full GR20. Runners can choose to run the route either south to north or north to south, and you'll just want to make sure that you plan your transportation in advance (more information on trip planning can be found here).
Regardless of which direction you choose to run, come prepared for some rugged, high, and exposed terrain. The overall route features over 40,000 feet of elevation gain and loss, much of which is on steep trails at higher elevation (much of the trail is above 5,000 feet above sea level).
Along the route, you have the option to book overnight stays at the huts along the route or you can pack and pitch a tent in the designated area around each shelter. The huts have basic amenities and need to be booked in advance during peak season from the Regional Natural Park of Corsica. More detailed information can be found online.