There are two commonly used climate zone scales:
- The US Department of Agriculture Plant Hardiness Zone Map (including zip code lookup) is based on the average annual minimum winter temperature, divided into 10-degree F zones. Santa Clara County includes zone 8b, 9a, and 9b.
- The Sunset Western Garden climate zones are based on length of growing season, timing and amount of rainfall, winter lows, summer highs, wind, and humidity. Their zones are included with plant descriptions in their Western Garden Book. The Central California Climate Zone map shows zones for Santa Clara County (including 7, 14, 15, 16, 17) with a description of the characteristics of each zone.