Marine effects in Southern Oregon, Northern and Central California
The climate in this zone features mild,wet, almost frostless winters and cool summers with frequent fog or wind. On most days and in most places, the fog tends to come in high and fast, creating a cooling and humidifying blanket between the sun and the earth, reducing the intensity of the light and sunshine. Some heat-loving plants (citrus, hibiscus, gardenia) don’t get enough heat to fruit or flower reliably. In a 20-year period, the lowest winter temperatures in Zone 17 ranged from 36 to 23°F (2 to –5°C). The lowest temperatures on record range from 30 to 20°F (–1 to –7°C).Of further interest in this heat-starved climate are the highs of summer, normally in the 60 to 75°F (16 to 24°C) range. The average highest temperature in Zone 17 is only 97°F (36°C). In all the other adjacent climate zones, average highest temperatures are in the 104 to 116°F (40 to 47°C) range.