Skidrage, WELCOME TO THE BOARDS!
Madrid is pretty cold right now. Thats' the word, directly from my contact in Madrid(gf lives there
). However, last year at this time, my friend that worked at a hotel resort in Marbella, told me that people aere still laying out at the beach because the weather was much warmer there!
Dmac is in Italy right now, and I just read a post of his saying that it's cold there now. "Bring a warm jacket, gloves, and maybe even a scarf," I believe that was the word from mac daddy.
Reserving hostels is a good idea, for the small popular hostels. Other than that, I think you'll do fine by winging it, unless it's a holiday or some sort of festivity is happening in the town that you're visiting.
Here's a list of
Barcelona hostels that may help you. Gat Raval and Pension Bahia are constantly mentioned and voted as great hostels.
If you go back into Madrid, maybe you already tried it, but
Barbieri International in Madrid is constantly voted a Top Ten hostel, and in fact, voted one of the TOP TEN hostels world wide in 2002! It is small and gets packed quickly, so if you do plan on staying in Madrid and want to stay there, it's a good idea to at the very least, pre-book that one.