The door opens, your dog sees wet pavement, and they back into the hall. Some dislike the sensation of rain or cold feet, others are worried by thunder or wind. A dog who is frightened of a storm needs a different approach from one who simply prefers a dry spot.
For a rainy toilet trip, choose a sheltered, safe place if one is available. Use a lead, keep the trip calm, and reward your dog warmly when they go. A properly fitted coat may help a dog who dislikes the wet or cold, but do not force clothing onto a dog who finds handling frightening. If there is thunder, lightning, or severe wind, keep safety first and wait for a safer window where possible.
Practice outside the crisis
On dry days, teach a predictable toilet cue by saying it as your dog starts to go and rewarding afterward. Later, try a brief trip in light rain, not a severe storm. Let your dog explore and return indoors without insisting on a long walk. If they come back without toileting, supervise and offer another safe opportunity soon rather than scolding for an accident.
If your dog is straining to urinate or unable to pass urine, seek emergency veterinary care now. If they show other signs of illness, contact your veterinarian promptly. That is not a weather-training issue. If storms trigger panic or escape attempts, talk to your veterinarian about noise fear. The aim is a workable toilet routine in bad weather, not proving your dog can stand through a downpour.
Sources: American Kennel Club: Why Is My Dog Having Trouble Peeing?. American Kennel Club: Training Dogs to Potty in Rain, Snow, or Bad Weather. Dogs Trust: How to keep your dog safe and happy during a storm.