A curtain suitable for attachment to the perimeter of an umbrella has a flexible sheet with an upper edge, a lower edge, a first side edge and a second side edge. The flexible sheet also has a front surface and a rear surface, each surface defining an area between about 8 square feet and about 120 square feet. Still further, the flexible sheet has one or more upper edge fastener portions disposed proximate to the upper edge for attaching the upper edge to a foreign surface, and has reversible retaining means for retaining the lower edge at a plurality of locations on the flexible sheet above the lower edge. The reversible retaining means are adapted such that, when the upper edge is attached to an umbrella, the vertical distance between the upper edge and the lowermost portion of the flexible sheet is adjustable by the user without the use of tools.