The Viking primary mission, principally covering the northern summer, has provided observations of a season previously unstudied from close range. The morning formation stage of the clouds, apparently orographic, associated with the Tharsis Montes and Olympus Mons, shows northwest slope clouds developing in late morning, at which time, discrete clouds, indicative of convection in a ~6-km layer near the surface, are formed over much of the elevated terrain. Low-level morning condensate clouds, or fogs, are associated with the canyons of Labyrinthus Noctis at this season. In Memnonia, at only 15¿S, CO2 frost condenses on the surface at night over a large area. The southern winter polar cap reaches 40¿S, having an irregular margin about 10¿ in width. Frost deposits within the cap are nonuniform and patchy. Discrete clouds have been observed at mid-latitudes in the south reaching 50-km altitude. One example of a local dust storm has been detected, but generally, the season has been one of comparative calm, having a relatively clear atmosphere in the south and dust and condensate hazes in the north.