Pimpasaurus

I just wanna leave this here for anyone who feels like evolving friendship pokemon can be too much work, but the fastest way for me is to get the soothe bell from the salon, then run back and forth in the area you obtained them and you should get happiness up enough to evolve in like 15-20 minutes, also use the salon treatment on it.

Apparently after extensive research for this same issue. I believe you have to wait till after Aya or Serra, I'm not sure which, time/weather doesn't matter as far as I know.