Additionally, if it's winter, you'll have a 15% chance of finding Vanillite around Route 6. They are missing in other seasons. The reason they appear in Cold Storage year-round is because it's so darn cold there.
I was wrong. But I've never met a Vanillite near the Cold Storage.
Plus, on my first approach, I didn't considerate Vanillite as a real ice pokemon. I thought he's bad (in front of cryogonal...). But since I read your post, I caught a Vanillite on road 6 and I'm happy to have him in my team (he's not too bad).
Thanks for your advice I'll win easily against Iris now.
Clay is not really hard. A good water pokemon or ground. And his badge is our. I did it with my Foongus level 31. (I have also used Darmanitan to achieve his excadrill but just because my Darmanitan held the rune coin to double my money).