Diamond Peak does not have any snow or ice bodies according to the U.S.G.S. (see map at left). However, up to at least the late 1920s, the peak held five glaciers (symbols on map at left).
Diamond glacier (ice blue symbol) flowed from the summit and was last recorded in 1938 (see comparison photograph at lower left). However, OGI received a photograph from 1971 (see photograph) that showed this glacier still in existence based on the convex terminus. Thus, this summit had a glacier during the period covered by the U.S.G.S. topographic map series. In fact, at the end of some summers lingering ice (likely refrozen snow melt) can be found on the peak, showing the propensity of the region to grow glaciers if the climate was colder than today.