a couple of notes on
CLIMATE & WEATHER
of Central California's Sierra Nevada Foothills
The graph at the right shows average monthly temperatures and precipitation for Placerville, located in the central Foothill zone. The precipitation is nearly all rain, and any snow that falls quickly melts. The very dry summer months certainly amount to a marked dry season
Summer maximum temperatures at Placerville usually range between 80°-93° F while winters minimums usually range between 22°-34°.
A very important feature related to the summer dry seasons is that at that time the danger of fire is very great and forest and brush fires are common.
You can see what the current weather is like right now in Placerville, in the Foothills east of Sacramento, below:
PLANT & ANIMAL ADAPTATIONS TO THE CLIMATE
The very dry, hot summers exercise a profound effect on Foothill plants and animals. One reason is because of a fundamental principal of ecology -- that the lives of plants and animals are disproportionally affected by extreme conditions. Thus if a plant or animal dies when the temperature reaches the freezing point or below, it doesn't matter whether all through the year the temperature is just right for the organism. When the temperature reaches freezing, the organism will die, and maybe its entire population will be wiped out over the entire area.
Since the hot, droughty summers are the most immoderate feature of the climate, Foothill plants and animals typically show obvious adaptations to summer drought. Many annual plants live their entire lifecyles during the rainy months, then pass through the summers in the seed stage. Most woody plants show adaptations to fire. Some burn completely, then resprout from underground parts. Others are protected by thick bark. During the dry season the foothill landscape is straw colored, except for perennial plants with very deep roots.