For dogs with a mild affliction you can try a bone, squeaky toy or a kong–bring this “special” distraction out only when it storms. Another solution for mild afflictions is white noise or soothing music. This works best in an interior room dampening the sounds of thunder and removing the flashes of light, which increase the fear.
Dogs that have a greater fear sometimes feel better in a tight space like a bathtub, walk-in closet or crate. Let them seek this out on their own and then make sure the space is always available. The security of a small space comforts them. If you take this one step further (and I didn’t believe this) putting them in a snug t-shirt gives them the sensation of being wrapped and protected. Use one of yours or pet stores carry them now (they are called “anxiety wraps”) some with magnetic properties. Like I said, I didn’t believe this but if you think of yourself on a stormy day “curled up with a book” in a cozy space or on your couch with a throw it makes sense. How about in the middle of the night when you burrow further under your covers? Basically, it’s the feeling of exposure that you’re alleviating.
DAP seems to be another great solution, Dog Appeasing Pheromone. There is a pheromone present in the milk of a mother nursing her newborn pups. This pheromone calms and soothes newborn puppies, placating them in their strange new environment. Taken one step further you can buy this pheromone, spray a little on their collar or bandana or get the plug-in diffuser.
Some people have used homeopathic remedies or flower essences found in health food stores or pet stores. Rock Rose, Five Flower or Mimulus are a few. Please check with your vet for their opinion and dosages.
Good luck with your dog and bring on the weather!