Color-shaded and contoured images of global gridded instrumental data have been produced as a computer-based atlas, available to the climate community through Internet. Each image simultaneously depicts anomaly maps of surface temperature, sea level pressure, 500- mb geopotential heights, and percentages of reference period precipitation. Monthly, seasonal, and annual composites are available, in either cylindrical equidistant or Northern and Southern Hemisphere polar projections. Temperature maps are available from 1854 to 1991, precipitation maps from 1851 to 1989, sea level pressure maps from 1899 to 1991, and 500-mb height maps from 1946 to 1991. All images exist as GIP (Graphics Interchange Format) files (1 024x 822 pixels, 256 color) and can be displayed on many different computer platforms. A Compact Disc Read-Only Memory version of the atlas is also available.