Hello,
Here in Arizona we are staring what is called the 'monsoon' season. These are rain storms that pop up suddenly, tremendous rain, lighting and thunder and haboobs (look it up). Below is some sound advice. I did not write it and will give credit to AKC.
Good Advice to know;

Dealing with Thunderstorm Phobias
Summer is here and in addition to sunshine and summer fun comes thunderstorms.

For many dogs, thunderstorm phobias are a big problem. Changes in the barometric pressure, the loud crack of thunder, the sounds of wind and hard rain, and flashes of lightening can all cause fearful reactions. Panting, pacing, drooling, quivering, and trying to hide are some of the signs your dog has developed a fear of storms. In some cases, dogs who have no issues with storms develop a fear later in life.


There are some things you can do if your dog is thunderstorm phobic.

1. Maintain a cool and level head yourself. Use a cheerful voice, don’t act afraid, and don’t baby the dog.
2. Even though you may not like your dog drooling on you and shedding large amounts of hair from stress, don’t show any signs of being upset with your dog.
3. Reduce the sound of the storm by turning on the television or radio and moving to a room that is quiet.
4. Try an activity that can distract your dog such as ball play or another favorite indoor activity.

For many dogs who are afraid of storms, offering a safe “den like” place is a great solution. Cover the dog’s crate with a sheet, or give your dog access to a room with no windows such as a bathroom.

Good Day~