Late spring, summer, and early fall are usually the months when fleas and ticks are at their worst. Some areas have nice climates year round, these areas have year round fleas as well. Your dog may be an inside dog; that does not mean that he is immune. Just taking your dog out to use the bathroom can start a flea infestation. A variety of other animals (stray cats and dogs, squirrels, etc) comb neighborhoods, these can very easily drop unwanted visitors at your door, literally.
There are products on the market to help control the pests that get on your animal as well as those that get in your yard, your vet can recommend the best products for you to use for your dog’s safety.