When to hike the GR20: the best time to go
The classic window is mid-June to mid-September. Inside it, the trade-off is simple: early summer means possible snow up north, midsummer means heat and crowds, September means quiet and shorter days.
The GR20 spends most of its ~177.5 km between 1,000 and 2,200 m in real high-mountain terrain, so the season is set by the mountains, not the Mediterranean beaches below. Two dates anchor everything: snow clearing from the northern passes (typically through June) and the refuges' staffed season, roughly mid-May to early October.
Month by month
| Month | Pros | Cons |
|---|---|---|
| May | Very quiet trail, refuges start opening around mid-May | Snow still on northern passes, limited services, unsettled weather |
| June | Long days, wildflowers, quieter than midsummer | Snowfields can linger on the high northern passes, especially early in the month |
| July | Trail fully clear, all services open, sociable atmosphere | Hot, busy, refuges fully booked early — reserve furthest ahead |
| August | Stable conditions, everything open | Hottest and busiest month; afternoon storms possible; book very early |
| September | Quieter, milder temperatures, beautiful light | Days getting shorter, first hints of autumn late in the month |
| October | Solitude for self-sufficient hikers in the very first days | Refuges close in early October, short days, increasingly unsettled weather |
Snow in the north: the June question
The northern half crosses passes above 2,000 m, and snowfields regularly survive there into June. After a snowy winter, early-June hikers may face steep residual snow on north-facing slopes — manageable with experience, unpleasant without. If you are set on June, check recent condition reports before you fly, and consider walking south to north so you reach the high northern passes as late — and as snow-free — as possible.
Weather realities in every month
Corsican mountain weather follows a reliable summer script: clear mornings, clouds building over the ridges after midday, and a real chance of afternoon thunderstorms — most common in the heart of summer. The routine that follows from this is the single best piece of GR20 advice: start early. Leaving at first light means you cross the exposed passes before the storm hour, walk the big climbs in the cool, and arrive at the refuge with the afternoon free. Heat is the other constant of July and August: the long descents to Vizzavona or Conca can be punishing by mid-afternoon.
Matching your dates to your bookings
Your month choice drives your booking strategy. July and August demand reservations as soon as your dates are fixed; June and September give you a little slack. Either way, every night on the trail — including bivouac pitches — must be reserved in advance, so read the refuge booking guide before buying flights. And decide how many days you actually need first: our how-many-days guide breaks it down by fitness level.
Set a start date, see your dates per stage
Pick a start date in the planner and it shows the calendar date for every stage and overnight stop of your itinerary.
Open the GR20 plannerFrequently asked questions
What is the best month for the GR20?
For most hikers, late June or September: the trail is clear of snow, refuges are open, and the crowds and heat of July–August are avoided. September in particular offers quieter refuges and softer temperatures, at the cost of shorter days.
Is there snow on the GR20 in June?
There can be. Snowfields regularly linger on the high passes of the northern half into June, especially after snowy winters. Early-June hikers should check current conditions and be comfortable crossing residual snow; by late June the trail is normally clear.
When are the GR20 refuges open?
The PNRC refuges are staffed roughly from mid-May to early October. Outside that window there is no warden, no meals and no bookings — the trail becomes a self-sufficient expedition. Booking remains mandatory in season; see our booking guide.
Can you hike the GR20 in July and August?
Yes — it is the most popular period, with all services open and a lively trail community. The trade-offs: the biggest heat, the biggest crowds, and refuges that sell out earliest. Book as soon as your dates are fixed and start walking at dawn to beat the heat and afternoon storms.