I did my first camino from SJPP starting at the end of Mar, just before Easter that year. I took thermals which I used as a base layer in the Pyrenees, but by the time I reached Arneguy, that was overkill, and I removed them. Thereafter, I used a three layer approach to start each day:
- base layer - wool blend tee-shirt / briefs
- mid layer - long sleeve trekking/travel shirt, long trekking trousers
- warm layer - fleece jumper, although more recently I have worn my rain jacket in the morning instead of a fleece to keep the wind off.
On chilly days, I will wear my rain jacket or fleece as an extra, fourth, layer. On only one day on that first camino did I need to add an fifth layer to keep warm, and that was pretty early on when leaving Logrono on a particularly chilly morning. This was more difficult, as this was going to be either an extra tee-shirt or an extra shirt, and both required stripping back to the point where I could get that on. That wasn't particularly pleasant.
My packing now contains two of my base and mid layers, one being worn and the other in my pack. But now I add a pair of shorts and a long sleeved tee-shirt to wear at night and which can be used as a base layer if it looks like being a particularly chilly morning.
As a matter of practice, if I wash and there are things that aren't completely dry, I will bite the bullet and wear these at the start of the next day. This ensures that I have a complete set of dry clothes should I need them during the day, and then when I arrive where I am staying at the end of the day. In fine weather, I can wear my shorts and long sleeved top around an albergue, but if I want to go out to look around a town or have a meal, I need more than that, and will change into that dry set of clothes.
ps the thermals went into the mail when I got to an open post office after Easter.