"An early decision has been taken because there is the potential for more rain in the next few days and our focus has to be on getting the surface right for the games against Glasgow next weekend and then the start of the Guinness Premiership against Leicester."
Gloucester's head of sales and marketing Pete Grzonka added: "The open day is a wonderful way to launch the new season at Kingsholm and although we considered other options around the stadium, access to the pitch is key and we had to take advice from the stadium manager in this instance.
"Naturally, we are very disappointed and we will certainly look at other options once the season has started. We hope supporters can understand the decision because of the highly unusual weather conditions.
"The launch of our season will now be against Glasgow a week on Saturday."
Tickets for the Glasgow game and the opening clash of the Guinness Premiership season against Leicester on Sunday, September 7 (4pm) are available from the ticket office, online at www.gloucesterrugby.co.uk or from the hotline number on 0871 871 8781.