Whilst Spain is renowned for its excellent sunny weather, this does not apply to the whole of the country, and it does get cold in winter - in some places more than in others. On the Atlantic coast (in the north) there is significant rainfall and is much cooler year-round, similar to the UK.
It does however have spectacular scenery, rugged coastline and impressive estuaries called rías, particularly in Galicia. Inland Spain has more extremes of weather in that it normally freezes in winter and bakes in the summer. It gets particularly hot in the south in summer - Sevilla can be well in excess of 35C.
The long Mediterranean coast is in general a bit wetter but milder year-round. The well-known Costa Brava, Costa Blanca and Costa del Sol coasts enjoy the warmer Mediterranean waters (over 20C in summer) and have miles of superb beaches that make these areas the most appealing to both visitors and expats alike.
The Balearic Islands of Mallorca, Ibiza and Menorca tend to be slightly wetter and winder than the mainland Mediterranean coast but with warmer waters (usually 25C in August).