Retrofestival has been entertaining thousands at Newbury Showground over the weekend. Today (Sunday) is the final day of the event dedicated to music, memorabilia, classic cars and vintage markets. Audiences have been lapping up the sounds and sights of yesteryear, and there is more to come. Three stages are set up for a variety of acts across the weekend, and there is an airshow and an arena area. What will the weather be like at Retrofestival on Sunday? Hot. Very hot. Until mid-afternoon, it will be sunny and cloudy, then from 4pm the skies will clear and it will be brilliant sunshine. The h…