A comparative analysis is made of the distribution of long term monthly mean temperature and precipitation data for three representative locations in the Alaska interior basin. Examples of extreme monthly conditions over the region are selected by reference to the record at Tanana dating back to 1903. The characteristics are outlined of the mean monthly orientations of the 700-millibar troughs and ridges and also the patterns of geopotential anomaly associated with summer months which exhibit extremes of warmth, cold, moisture and dryness. A comparison is made between these patterns and those that have been postulated for the time of the maximum Wisconsin glaciation.