Previous years I've been in Sept it's cooler than August but still high 20s, you might get odd cloudy day and odd storm but generally it's still hot. The only thing I have found is that it gets cooler at nights so you might need long sleeve top sometimes.
At the min its not good rain and thunder storms Im off on fri and am going to pack light jacket combats t-shirt stuff just incase, but I went last year at the same time and the weather was great just a wee bit cloudy, it varys
Thanks K.H! Im soooooo excited! We are having an Ibiza return Nonsense on Sunday 29th September as we all arrive back at 6am and we are running our bankl holiday special that night if you fancy coming along? Its in Adlib on hope street!