Spring to late Fall, warm days are 65 to 85 degrees, with cool evenings from ocean breezes.
Summers are dry.
Winter days are pleasant with chilly evenings. Rainy season is broken by spar-kling clear, sunny days. December through February, high tempera-tures range from low 50s to 65. Petaluma had the world's first and only chicken pharmacy. A Canadian-born Petaluman, Lyman C. Byce, is credited with invention of the first practical chicken incubator in 1879, opening the way for Petaluma's chicken industry.