Murrieta is located some 20 miles from the Pacific Ocean. The Rancho California Valley is cooled in the summer by afternoon breezes and protected in the winter from the harshness of northern snow and ice. The climate is influenced by marine air, which flows through a gap in the mountains. The mean maximum temperature in August is 87 degrees, and in January is 61 degrees. Due to cold air draining into the Pauba Valley, low-lying areas occasionally experience below freezing. Due to the prevalence of sea breezes throughout the area, oxidant levels are relatively low. Smog occurs mostly in the late summer and virtually never in the winter months. Population about 75,000.