For many dogs, thunderstorms mean fear and trembling, for the unluckiest dogs they mean outright panic.
The standard therapy for dealing with fears in dogs is counter-conditioning and desensitisation. You start desensitisation by exposing your dog to the frightening stimulus in its mildest possible form. You counter-condition by pairing the scary thing with a super-special treat. When your dog understands that he’s survived the stressful event, he will begin to calm and be less afraid. 

With thunderstorms, two factors are important;

1. First, counter-conditioning and desensitisation largely depend on avoiding random exposures to the scary thing. This can be difficult when dealing with the environment.
2. Second, a thunderstorm isn’t just one thing. It includes a darkening sky; the smell of ozone; changes in barometric pressure; wind and rain; lightning and thunder.

Play Therapy – Useful if your dog is only mildly anxious, maybe a little restless, before and during storms. The minute you’re aware that a storm is coming, bring out the ball or tug toy. If you throw a play party whenever there’s a storm, your dog may learn that storms predict good times.

Behaviour modification and medication – Unfortunately, you won’t always be home when a storm comes, and every episode of anxiety makes it likelier the anxiety will worsen. If you don’t see clear improvement after a couple of storms, or your dog is highly anxious, consult your vet and use the steps above in conjunction with anti-anxiety medication. 

The good news is almost all thunder phobic dogs will see significant improvement either with gradual exposure and use of counter-conditioning and desensitisation alone or coupled with prescribed anti-anxiety medications.