I walked in October and half of November and found it to be a great time to walk. The massive throngs will have gone and there will be more than enough fellow pilgrims to make the 'Way' extremely interesting. I found most albergues still open and there was always room in them, even though some were still close to being full-Finisterre, for instance. Now it was cold that night in November, though. So, while you will have missed the wildflowers blooming in spring, you will walk through the massive vineyards during the harvest of the most delicious , as well as freshest, grapes you will have ever eaten, while crossing Navarra and La Rioja. October is a fine time to go. Going then, the cold of the higher elevations will still be bearable when you cross the mountains into Galicia and, walking the entire way in shorts is a direct possibility. I did so, anyway