The climate is rarely hot, but is warm and it is often rainy and overcast. I'd suggest short sleeves with a sweater and a light rain jacket, a pair of summer jeans and some shorts, a pair of long pants. The temps are typically in the mid-70's during the day, but only about 1 day in 5 are sunny. If you are near the mountains, expect cooler weather. If you'll be near the sea, be sure to take sun block and swim wear for the good days.