The quality of air in Temecula Valley is consistently better than that of surrounding areas. The yearly average rainfall in Temecula is approximately 14 inches, as compiled by the Rancho California Water District. Average summer highs are 85 degrees winter lows 39 degrees. These weather factors combined with the perfect balance of great geography create an ideal environment for growing high-quality wine grapes and experiencing a variety of outdoor activities.Īlthough separated from the Pacific by the Santa Rosa range, the Rainbow Gap funnels the mild beach climate into the valley. The valley's unique microclimate makes for a general year-round pattern of morning mist, warm midday sun, cooling afternoon breezes, and cooler nights.