May to June or September.
I went in June and I would say this was a good choice.
Part of the track is in quite high altitude and that makes it chilly at night, also indoor.
Of course, there are less people in October to April but even in June I never felt it was really crowded.
For sure people will always say that years ago it was better. It is a favorite thing to say for travelers, no matter where you are.
July and especially August is too hot for walking.
Because of the altitude (not only the pyrenes) it might be cold at night. Accommodation (“albergues”) doesn’t have insulation which we know from Central Europe. So take a light- weight sleeping bag.
Be prepared for rain, too. I experienced all kind of weather including hail one afternoon.
Since we talk about Europe you don’t have to worry about the naughty, “exotic” diseases like Malaria.
Biggest concern should be your back, knees and feet. All this leads to light backpack. Don’t take 12kg. It is NOT necessary. Everyone can make it with 9kg. Yes, you can. And your body will be thankful.
We talk about the “camino francès”. It starts in St Jean Pied de Port (France) and will take you in about one month to Santiago de Compostela or Finesterre at the Atlantic (2-4 additional days).
Anyway you think you will be okay carrying 1-3 extra kilos, which you think you need. You might be okay for a week or two but later you will feel those kilos!
I had knee problems. Awful. Slowed me down a lot. They called us the "walking dead". ;-) Still I walked every day. Many other people have blisters. Pretty sure you will have some issues.
There are one or two horror stories. It is always the same story but considering how many people walking the camino every year, I am pretty sure the camino is safer than your home town.
You will see thaat everyone leaves his belongings on and around the beds in the "albergues" (accommodation). Never heard of stealing. No one wants to carry additional stuff. ;-)
The infrastructure is great. Not fancy, but all you need. I expected the albergues to be like bad hostels but actually they are like good hostels. Rather clean. I think they improved a lot in the last ten years.
Food is always available in the villages.
No bus, no train, no car: Just walking... :-)
but actually not worry, if you need to bus (pain or lazyness), there are (public) buses.
I think there is no cheaper way to experience Spain.
A bed in a dorm (albergue) is 5-10 EUR per night. (No, it's not free).
Some places are "dornativos" which means you donate for your stay. Usually they are so good that you will pay more than for an average albergue.
Food is rather cheap in the bars / restaurants along the camino.
Well, this is not so much of a question. There is no need and not often the possibility to prebook.
If you finish walking at 3pm, you will always find a bed to sleep.
If you finish by 6pm, it will still be in 90% of the cases. What to do in the other 10%? Don't worry. You are a pilgrim and there are many other pilgrims. People will help you. Other pilgrims or locals. In worst case you bus back one village or one ahead. You will find something!
Enjoy the landscape. especially at the beginning in the pyrenes the mountain view is very nice. And you have no pain yet. ;-)
Enjoy the food. After a while the food, especially for breakfast, gets kind of monotonious. But still, food is good. Santiago is located in the region of Galicia. The landscape and the dishes change there and they are great! :-)
Enjoy the wine and the great company. You will meet a lot of people and for many this is the best part of the journey. But if choose to be on your own, especially walking alone, people will totally accept it.
I did the camino francès. So the French way. It is called like that because it "starts" in France. Most people start in St.- Jean- Pied- de- Port. This means you walk half a day in France and from then on in Spain. I didn't even realize when I crossed the border.
And then you go to Pamplona (famous for the bull run) - - Logrono -Burgos - Léon - Santiago. Just to name the biggest places.
There are other caminos. All of them are less frequented. There is the Basque one in the North, going along the Northern coast line.
You can start earlier in France, e.g. in Le- Puy- en- Velay.
And there is the Portuguese one. At latest it starts in Porto but it is also possible to start in Lisbon.