Weather in Spain:
Best time of year to visit Spain is between April and June and September and November. July and August can be brutally hot. From December to March, the weather can be very chilly, especially inland.
The climate in the south and north of Spain is Mediterranean, with mild winters (the further north, the colder it gets) and dry, very hot summers. The western and northern coasts are somewhat cooler and more humid in summer, and the winters there are cold and rainy. Inland the weather is more extreme, with dry, very hot summer days (cooler at night) and dry but very cold winters. Pack warm clothing unless you plan to visit in the summer months (June to August), when light clothing, a hat and sunglasses are recommended. Don't forget a raincoat if you're going to visit the north or Galicia regardless of the season.