I'll be planning a trip to Key West during hurricane season, flying Southwest. Will having travel insurance make a difference should a hurricane hit, or is that up to the policies of the airline?

It depends on your insurance. Some policies will cover you in the event a storm forces you to cancel your trip. The same if an illness (either your own or that of an immediate family member) causes you to cancel your trip.

Not all travel insurance is created equal. You need to read the policy to ensure that you are getting one that will meet your needs.