Where are you starting from, going to? Are you going high up? The cantabrian mountains and the picos de europa are an extension of the pyrenees and go up to 2500/2600 metres. At that time of year I've had at times very hot weather and also over a metre of snow higher up within 24 hours. It can be very changeable, although never really too cold unless windy.
Rain. That part of Spain isn't called 'Green Spain' for nothing, and suffers all the Altantic low pressure systems we get. The lower hills are extensively wooded with chestnut and very lovely. The higher Picos are mainly limestone, rough under foot and with few water sources. The local food is generous, simple and good. The people much the same. One of my favourite places in Europe - have great time.
Wow what an adventure i've just come back from the Pyrenees, be sure to check out the Mountain Alas. I was based in La Seu D' Urgell which is close to the country of Andorra. January and Feb are the coldest months. I found the climate to be pretty similar to the UK.
