With a Mediterranean climate, El Cajon has warm and dry summers, and mild and wet winters. The city is situated in a valley and is surrounded by mountains, with the San Diego River running through it. The river is a crucial source of water for the city, but it is also prone to flooding during heavy rains. Outdoor recreation opportunities in El Cajon include hiking and biking trails in the adjacent mountains, fishing and boating in nearby lakes, and golfing at several golf courses in the area. The city also has several parks and playgrounds for families to enjoy.
El-Cajon receives approximately 355mm of rain per year, with humidity levels near 74% and air temperatures averaging around 18°C. El-Cajon has a plant hardyness factor of 10, meaning plants and agriculture in this region tend to thrive here all year round.