I was there last year from 22nd September for 2wks, the temperature was roasting (well for me anyway) the first week we had a few days of pouring rain - good excuse for a visit to the pub though. Once that had cleared it was back to being absolutely gorgeous even in the evenings it was warmer than usual.
We are going back at the same time this year and hoping it doesn't rain as my brother and his girlfriend are coming in our first week for the first time (hoping to convert them to Icmelerites

). For October the weather usually about the same as October.