How to Keep cool on wedding day?!

I am getting married in a church, completely air conditioned. The reception is at a venue/hotel, completely air conditioned, it a huge area. People will not be hot inside and again guests can decide for themselves to go out or not. All food and drink is inside they do not need to even step outside at all.

Then I don't understand the point of anything being outside? Why would you think that guests will be go outside? Can they all fit inside? And is inside air conditioned?

IMO, this whole thread makes no sense whatsoever. Your original post states plainly " I have a long dress that has 3 layers and our cocktail hour and photos will all be outside." Now you're saying that cocktail hour actually won't be outside, but guests can wander out if they want. That sounds like a change in your story based on the comments to me, but maybe that's just me.

If you want to stay cool for your photos, do them fast. Problem over.

Agreed with @elizabeth it seems like the more you clarify the more none of us understand the point.