Early September Camino--silk liner only?

I walked from SJPP to Santiago beginning in early September and I remember the evenings being quite warm until Leon. Then the weather began to change and Galacia was wet and cold. I took a 300 wt fleece blanket cut smaller (weighed less than a sleeping bag and was easily washable) and used that with my silk liner when I got cold. It worked fine for me and there were a number of places that did not have blankets (plus with bedbug scares I'm not too inclined to want them). I am thinking that walking the Portuguese from Sept 9-22nd that I might not need the fleece? What weather/temps did you encounter in September? Just 11 weeks to go!