I like either for a wedding, both very suitable, but I’d agree that red isn’t as much of a summery colour.
I would give you a word of warning about Chi Chi though. I loved so many of their dresses and ordered some as I had a few weddings coming up. I think the quality is very hit and miss - a couple were nice but a couple of them were awful quality. Definitely have a back up option, but if the wedding isn’t until next summer then you have plenty of time to look around 