Temperatures in early Oct in O Cebreiro

Here are last October's figures from O Cebreiro and Foncebadon (the closest village to the Cruz de Ferro). Of course this year may turn out quite differently...

Nobody can advise you with any confidence. These places are at altitude, and weather is wildly erratic. I was there in early to October one year, and it was 20 C under brilliant sun. It could just as easily been snowing. Be prepared with layers in case of cold conditions, but hope for perfect. You don't need to pack a parka just in case. Wearing your base layer, long sleeve, fleece, and rain jacket all at once, you will be fine.