Health & WellnessIs fall truly the worst season for pet flea infestations, and why?
Yes, in most temperate climates, fleas are at their worst [through the fall](https://www.petcoach.co/article/fall-and-fleas-what-you-need-to-know). Like all insects, fleas go through a life cycle where adult fleas lay eggs, which mature to larvae, then pupae and into adults that lay eggs of their own. None of these life stages can survive when temperatures drop below 37 degrees Fahrenheit unless they are already surviving on a host, such as a household pet or wild animal, or are already inside of a warm home. As temperatures warm up in the spring, fleas begin to boom, with adult fleas laying around 2,000 eggs over a two-month span. With consistently warm temperatures, these eggs typically mature into egg-laying adults within three weeks. Consider what happens as these 2,000 eggs mature and each lay 2,000 eggs of their own! The flea life cycle continues to boom until the temperature begins to drop by late fall, making fall the time of year where fleas have grown to the largest population size. In climates that stay above 37 degrees Fahrenheit year-round, there is no reprieve to the flea life cycle. Many pet owners lapse in their use of flea preventives in the fall, which provides fleas with an accessible and unprotected host. In all instances, it is best to keep your pet on a good-quality flea preventive medication consistently year-round. Since all flea preventives are not the same, it is best to discuss the best option for your pet with your veterinarian.
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Updated on September 24th, 2025
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