Spain is already full of golf resorts and more are being built all the time. So, there is always a resort to suit everyone's requirements (on the coast, in the mountatins, easy course, championship class, other activities available, family oriented etc, etc).
The weather is generally pretty predictable so you would be unlucky to be completely rained off (in fact they'd probably appreciate a bit more rain!).
Arguably one of the best spots for golf in Spain is the Costa del Sol where there are nearly fifty courses over a fifty mile stretch of coastline.
The only downside of playing golf in Spain is that, I guess because it's so popular, you generally have to book well in advance and, often, the game is a five hour marathon (they don't seem to press slow players on as they do in other countries).
So, all in all, from my perspective Spain is a much better destination than the Algarve (too expensive), France (weather too unpredictable), Ireland (too expensive and weather unpredictable).
What do others think? Have I missed somewhere worth considering? Is Northern Portugal worth a look (perhaps around Lisbon)?
