Sonoma County has many many micro climates, not only
with temperature, but also with precipitation. For example Santa Rosa averages
a little over 30 inches of
rain a year, but if you travel 10 to 20 miles away, rainfall averages are much higher. Cazadero
is in western Sonoma County during one year received 117 inches of rain!
Sometimes for several years in a row this town receives well over 50 inches of rain each year.
Downtown 4th Street park and State Building located behind the post
office
Santa Rosa tends
to have quite a bit of fog in the summer months but each summer can
vary in the amount of fog. Summer hot spells in Santa
Rosa rarely last for more then a few days. The temperature reaches 100
or over in Santa Rosa maybe 5-7 days out of the year if you are lucky. However, the
Upper Napa Valley, Healdsburg, or Cloverdale tend to be much warmer
then Santa Rosa in the summer months. However, Santa Rosa is usually a
bit warmer then these places in the winter.
Winter highs average in the high 40's and low to mid 50's. Weeks can go
by without temperatures much above 60 degrees F. Summers are very dry
and mild. Temperatures usually remain in the 70's and 80's.
Typically between the months of November and March
Santa Rosa receives a fair amount of frost and nights where the
temperature hovers at 32 F or several degrees below. Santa Rosa
definitely does not have as mild weather as say more central and
southern California. Because of the generally colder nights in the
winter its difficult to grow semi tropical fruit such as avocadoes or
bananas - although if you look carefully you can actually see a few
small trees around town.