The RHS said: "Sadly due to adverse weather conditions we've had to close RHS Chatsworth today - we hope to open as normal tomorrow."
TV stars Mary Berry and Alan Titchmarsh launched the RHS Chatsworth Flower Show in the rain at the Derbyshire stately home on 6 June. The show is due to continue until June 11.
Winds of 30-40mph and torrential rain hit the press preview day, with more mixed weather forecast for the rest of the week.
The RHS says nearly 90,000 tickets have been sold.