The most pleasant months of the year for Shamrock are May, October and September. In Shamrock, there are 4 comfortable months with high temperatures in the range of 70-85°. August is the hottest month for Shamrock with an average high temperature of 92.2°, which ranks it as cooler than most places in Oklahoma. January is the snowiest month in Shamrock with 2.9 inches of snow, and 4 months of the year have significant snowfall. The most uncomfortably humid months are July, August and June.