Need some help - What color coat?

Men wear suits to weddings and plan ahead more than 30 hours. So you need to scamble. At minimum you need a jacket.

You said navy pants so you're going to have to be in the brown or grey area mostly likely. Others will have to answer. I don't see an imbedded pic and am not clicking a file at work.

Blue, Blue, Blue and Brown at the bottom? That is difficult.

Also, you should not ask if you should wear a jacket if you are wearing a tie.

Maybe I will be flamed on SF for that but the shirt, tie, no jacket look is for children or maybe specific

very cutting edge looks that have little to do with formality of any type.

Belt color? Curiosity.

 

If your trousers are a dark or proper medium navy color, I think you are very limited.

Another dark navy up top will almost undoubtedly look like rubbish separates.

Black is out.

Dark grey the same.

I have a blue cotton jacket that would be along the lines I would look toward.

About the shade if you took the blue and white stripes of your shirt and mashed them into one color.

Obviously, there is the possibility of blending too much with the shirt but I think the white bars are wide

enough to give enough contrast from inner to outer.

I would look for lighter colored jackets. I do not know your location but it is sort of still summer and with those temps

a lighter color would be better than say, in a few feet of snow or by the fireplace.

Or if you care to rock a funkmeister vibe of some sort, maroon, etc.

Also, you can just find the approximate color of your navy blues and shoes and scribble a swatch onto the photo.

Are your shoes hard leather, mocassins, etc.?

Sorry to be such a douche but I am not sure there is a great answer. I would switch out something and make life much simpler

but I assume that is not possible at this point.

Well, I am not advocating you to be the only under dressed bloke at the wedding but there are some of those type events

that are quite casual(no jackets) in which case, dump the tie and you are sorted.

But since it is also very possible this is not the case and it is a fully dressed affair, see if there is jacket no tie happening.

While this does not solve your jacket buying issue, it eliminates a blue to make the color assortment a bit easier to handle.

Plus, a bit cooler. 

And whether tie or no tie, again, a light colored jacket is my best guess.

That is not so helpful but a start.

Very light blue.

I think a cream or along that line will be tough to pair with the shoes, I think.

A light grey might, somehow, work the way the light blue would.

In this case, I think I would prefer the navy trousers are not too dark to make it all easier but it is what it is at this point.

 

Overall, as long as you don't completely muck it up, you should be good and ready within the Chicago scene.

I saw 10x more girls under 30 with cankles in a month there than I have in all the rest of my life.

And they were some of the fitter ones. They just have  those cankles.

And why 98% of them wear flip flops no matter where they are is beyond me. I realize that it is not Milan and it is hot and they want 'comfort'

but c'mon now.

I hope flip flops are not at the wedding unless it is on the 'beach' by the lake. But then you can skip the jacket as a bonus.

OK, I am done venting.

 

Good luck

 

I'd also definitely go with a light coloured jacket.  An ideal combo is hard given your time crunch, but you could go with either light grey (tie optional), a la Mr. Beckham Goes to Washington (dailymail.co.uk/femail/article-2179712/London-welcomes-First-Lady-fashion-Michelle-Obama-dons-ANOTHER-patriotic-outfit-support-Team-USA.html) or powder blue (harder to find last minute, but if you do, lose the tie).

 

Good luck!