The length of flea season in California is going to depend on where you live in the state and the specific climate of that area.
Please note that fleas are most active when temperatures are between 70°F and 85°F and relative humidity is above 70%.
So if you live in Southern California, say Los Angeles or San Diego, flea season can be virtually year-round. The fleas will become less active at night time during the winter season when temperatures dip.
In the northern part of the state, where temperatures are chillier, flea season is shorter.
Please reference our flea image gallery below to view a map of the United States which depicts the length of the flea season by color codes to get a better idea for your specific location.