The texture of the sand plays a role with your clubface.
As a general rule, the fluffier or finer the sand, the more the clubhead will dig into the sand. Therefore, a more-open clubface is needed to let the bounce of the club do its job.
With coarse, heavier or wet sand, the clubhead will tend to bounce off the surface. Therefore, a more-square clubface at address is desired to allow the club’s leading edge to dig into the sand.