The answer to 'flea season' is that fleas are most active and prevalent during the warmer months of the year, typically from late spring through early fall. Fleas thrive in warm, humid environments and their populations tend to peak in the summer when temperatures are highest.
Flea season can vary depending on your geographic location, but in most regions, you're likely to see the most flea activity from around April or May through September or October. During this time, it's important to be vigilant about flea prevention and control measures to protect your home and pets.