Silicon valley is mainly a broad level alluvial plain averaging about 200’ above the sea level of the San Francisco Bay, nestled between the 2500’ high Santa Cruz Mountains to the west and the 4000’ ridges of Mt. Hamilton on the east.
Climate
The climate of Silicon Valley is a result of the latitude, topography and the close, but not direct, proximity to the vast Pacific Ocean, whose huge mass of water tends to moderate both high and low temperatures compared to more inland areas. The modest heights of the mountains provide some buffering from the full blast of the winter storms coming off of the ocean. Much of the rain (exceeding 50 inches of precipitation per year) from these storms is deposited on the windward side of the coastal Santa Cruz Mountains, leaving Santa Clara Valley in a rain shadow averaging less than 15 inches of precipitation per year.
Snow is virtually unknown on the valley floor, but the higher ridges of the surrounding mountains occasionally receive some winter snow. The relative scarcity of rainfall might create water supply problems if the projected reoccurrences of drought occur as suggested by climate change models. This will effect what species of trees will be able to survive such low rainfall patterns.
Seasons
Spring in March-May.
Summer in June-August
Fall in September-November
Winter in December-February.
Soil
Many of the soils of Santa Clara Valley are also conducive to tree growth. They are primarily rich clay loams that have sufficient natural fertility for good tree growth and are fairly water retentive helping the trees survive the long dry summer season. The soils in Santa Clara Valley have a neutral to slightly alkaline pH range of 7.0 to 7.6