I started on the August 21st in 2016 - be prepared for hot weather! It's a good time to start because it may be hot at the beginning, but temperatures should cool down as you get farther into September. Also, you will be ahead of the throngs of pilgrims who start from St Jean in September. Since you have plenty of time, I would suggest booking the first night at Orisson. It will break up the long climb over the Pyrenees (don't worry, it's not technically difficult, but it is a lot of uphill!). It will also give you more time to enjoy the Pyrenees, which are gorgeous, and you will meet many other pilgrims who you will likely see for the next several weeks. If you want to stay at Orisson it is important to book it as soon as possible, as they only have 28 beds.
Located in the heart of the Basque Country, on the GR65, between Saint Jean Pied de Port and the Bentarte Pass, REFUGE ORISSON is an ideal stopover before reaching the Lepoeder pass. It is the last accommodation before crossing the Pyrénées. Orisson’s position on route towards Roncesvalles...
refuge-orisson.com