In reply to Receiver16:
I think what others have said about variability is the key thing. I was there may weekend and although there was a lot of snow in since places you could get right to the top of some of the highest mountains without stepping on snow.
The previous weekend was completely different, with deep hard snow very widespread.
Temperature and rainfall are also very variable. Unless it's really cold softshell trousers with hardshell in the bag works well for me (I usually being thermals up as well, but they generally stay in the car). For the top half again variety is key, you can need anything from a t shirt (backup layers in rucksack) to full hardshell with layers underneath.
For spikey things if you're intending to go up high they're advisable often, but more up to date conditions can be found on the met office website. If staying low you may be on, bit might have to turn back if you get to things you're not comfortable with.