How long does skunk smell linger on a dog?

At least a couple of weeks, and maybe longer when the dog is wet or gets warm. Kind of depends how badly it was sprayed and what you did in the way of cleaning the dog.

My indoor/outdoor dog was sprayed at the end of April. We bathed him twice in the first couple days, once with Skunk-off, which did absolutely nothing, and once with a mixture of peroxide, baking soda, and dawn dish soap, which helped exponentially and eliminated the smell almost immediately.

That being said, when my dog gets wet, we still get a hint of skunk smell and it's been three months.

In contrast, my parents' strictly outdoor dog, who was also sprayed at the same time, got rid of the smell after about a month through his own devices.

There is a remedy (have had both my dogs skunked on multiple occasions) but since you don't want to know - it will lessen the time if you wash them frequently with detergent (like dawn and finish with hair conditioner) - probably 6 weeks to 4 months.

It's quite variable (it depends on just how much spray got on the dog). I would also guess that it depends on how active your dog is and how often it goes swimming. If I had to hazard a guess, a few days to a week or two oughta do it.