People often ask us "when should I walk the GR20?" so we asked Paddy Dillon to give us some advice on the best time of year to take on this challenging route.
Trekking the GR20 is not recommended until at least the beginning of June, although it is sometimes possible to start in the middle of May. Last minute travel arrangements can be made if you hear that the route is clear of snow, but those who plan well in advance are taking a big chance, and deep snow could affect the higher parts of the route. The presence of snow and ice on particular parts of the route is usually mentioned on the PNRC blog, randoblogpnrc.blogspot.co.uk. An ice axe and crampons might be required, as well as the skills to use them properly. Trekking at this time means that the PNRC refuges, although open, will not be staffed and therefore will have no food supplies. The water supply may be disconnected and there may be no fuel on the premises. Private bergeries may be locked and bolted. It will be necessary to carry most of your food, or it may be necessary to leave the route to obtain supplies. Bus services to and from the route will be fairly limited.
The picture on the left was taken towards the end of May and the GR20, up the gully, is heavily covered in snow; the one on the right was taken towards the end of July and the snow has gone
The PNRC refuges and private bergeries will all be fully staffed and in full operation. This used to be a quiet time to trek, but in recent years it has become very busy. The refuges will often be fully booked, and any hire tents pitched nearby might also be fully booked. Food supplies and cooked meals will be available at almost every overnight stop. Bear in mind that some snow and ice will still be lurking in some of the more sunless gullies, and could pose problems early in the month. Days will be warm, but not too hot. Some bus services to and from the route might not be fully operational.
July and August
These are the peak summer months on the GR20. Expect large numbers of trekkers and expect the refuges and hire tents to be fully booked. All services are in full swing and it is easy to obtain food and drink along the way. Bear in mind that a few seasonal water sources dry up. Should it be necessary to leave or join the route at any point, the full range of summer bus services will be available. This is also the hottest time of the year, with an increasing risk of afternoon thunderstorms. There have been devastating forest fires in the past around this time, closing parts of the route to trekkers.
This used to be a quiet time of year, when the numbers of trekkers reduced, but in recent years it has remained quite busy. The refuges will probably be fully booked, as may the hire tents, but as the month progresses it might be possible to stay indoors without an advance booking. Some of the bergeries offering food and drink may close, and some of the bus services to and from the route will be withdrawn. It is usual for the PNRC refuges to remain fully staffed and supplied with food to the end of the month. The days are cooler than the peak summer season, but remain warm and clear. After June, this is the best month to trek.
The PNRC refuges remain open, but are unstaffed and have no food supplies. While fuel might be available, it is best not to rely on it, and the water supply might be disconnected to avoid frost damage. Private bergeries will be locked and bolted, and any small food stores along the route will probably be closed, so it will be necessary to carry food, or leave the route at intervals to obtain supplies. Very few bus services will be available, although the train through Vizzavona continues running. Those who start the GR20 at the beginning of the month and aim to complete it by the middle of the month will experience cold nights and possibly frosts. After mid-October, snow could fall at any time. Snow obscures paths and waymarks, and when it accumulates on steep slopes, there is immediately a risk of avalanche. For ordinary trekkers, the route is closed throughout the winter, although ski traverses are sometimes achieved.
The High Level Route
Guidebook to walking the GR20 through Corsica's high mountains. A challenging trail between Calenzana and Conca that includes hands-on scrambling, the 190km trek can be completed by fit walkers in about two weeks. The guidebook includes high and low-level alternatives, plus extra mountain climbs, and all you need to know for this tough route.