Thirty five thousand people are expected to attend the sixth Latitude Festival, taking place this weekend at Henham Park near Southwold.
Tickets have sold out for the festival of music and arts, which will feature Suede, Steve Coogan, Ralph Fiennes, Sadler's Wells and Shappi Khorsandi.
Festival director Melvin Benn said he was not concerned by forecasts of rain.
"Brits in general are hardy people and I don't think a bit of rain will spoil the enjoyment."
Mr Benn, who said the "beautiful" surroundings of Henham Park had played a key part in the festival's success, highlighted Ed Sheeran and James Blake as acts to watch this weekend.
"The music is fantastic but when you couple that with things like Sadler's Wells and the National Theatre of Scotland you're looking at real quality."
BBC Radio Suffolk is broadcasting live from the festival throughout the weekend.