It is vital that you put your fabric gazebo down and packed away when there is rain forecasted. The main reason why you should do this is that it can cause serious damage to the gazebo. The rain may cause water damage to your fabric gazebo, which over time can make it unusable. Water sitting on top of your gazebo can cause the fabric to become mouldy and begin to rot away. This means the fabric will be damaged and will be more likely to break.
If you are only forecasted a small amount of rain, it may be okay to leave your gazebo up. If the rain is being followed by very hot weather, this will dry up the water, helping to prevent worse damage. If you do decide to keep your fabric gazebo up, you should always go out and remove the water from the roof to help prevent damage. This can simply be done by going underneath the gazebo and hitting it from below.