In May it's starts getting warmer, but you'd still have to wear a jacket. Also if you go there in autumn or spring make sure you have good/not expensive boots. It gets extremely muddy, there's puddles and dirt everywhere!!!
Coldrex, Lemsip - anything for flu and cold.
Don't forget your camera. There's a lot to see.
Bring mosquito repellant if you go there in May, June, July
