I had to make an A&P run, and took Caleb with me. Our weather forecast for the day is varying degrees of pouring down rain. Of course, I get caught in the worste of it going back to the truck when I was done shopping. No biggie, and His Royal Puppy Highness was high and dry in the front of the truck watching me (and laughing, I'm sure). Just as I pull into the driveway, it starts pouring again. Guess what- Caleb took one look at all the rain coming down, backed away from the opened truck door, and sat on the passenger side with a "What are you kidding me?" look on his face. I left him there while I took the bags in. When I went back to get him, he did the same dang thing. Good thing I put a harness on him when we're in the truck because I took hold of the front strap and gently pulled him to the open door so I could get him out (I don't have a problem leaving the rest of the groceries in the back of the truck indefinitely, but I wasn't leaving him out there like that).
I had one like that...a female...my ex has her now...I wonder how he is making out with the rain we've had lately. She would not go pee or poop in the rain. Totally loved the swimming pool but it was something about rain.
When we first got Chamois as a puppy and were trying to housebreak her, it was also winter in Houston (e.g. rain, and LOTS of it that year). There were a lot moments involving 3AM standing outside in my PJs under an umbrella with an unhappy puppy on the other end of a leash. We sometimes had to carry her out, since she wouldn't go on her own.
She's better now, but still doesn't really like it (note though, she does like swimming in the pool, it's just dripping or spraying she doesn't like). Toby, on the other hand, LOVES cavorting madly in the rain, in a hose, a sprinkler, anything with water...