This is a link to a proper weatherproof projection enclosure...
http://www.displaydevices.com/products/staging_solutions/epe.html

here as well...
http://www.tempestlighting.com/products.html

You are looking for a digital signage PC, which there are many (hundreds) to choose from.

You really should be going to a professional installation company for this work as it appears you know nothing of projection at all, you just are looking for a solution. For a professional solution when you don't know anything about the subject, I would turn to experts and pay them appropriately for their engineering time. Any commercial A/V dealer should be able to help you out.

I struggle with this as there are answers to your question on outdoor enclosures just a few posts down, so if you aren't willing to do this basic research, then you truly do need someone to help you get this done properly.

We used these guys for a number of projects from video mapping to a backyard theatre in Mozambique https://www.projector-enclosures.co.uk/outdoor-projector-enclosures/