Where do I find the weather overlay option for map on the Epix Pro 51mm? Thank you.

In the weather widget. 

Go to the weather widget... scroll to the map... press start... select change overlay.

I found it! Thank you for responding. I had a few issues with getting the Weather widget to work and update, but it seems to work now. This overlay is a huge neat feature that I'll use a lot! Thanks again.

Yes and when will this be available for Epix non pro? Can you also use this during an activity?

It will be available for non-pro models in the next major quarterly firmware release, around 2 months from now, or a few weeks earlier for Beta testers.

Currently, no you cannot view these weather overlays in the activity maps, they are only available in the weather widget. However I believe you can exit the activity (long-press the Back/Lap key) and then view the weather widget during an activity recording. I'm guessing they'll add the weather overlays to activity maps in the future, but I haven't yet seen any assurances that they definitely will, so there's no guarantees. A lot of people have been asking for it though.

Sorry but I have the same problem. I enter to the weather widget but no map view available? how i can get it? Model: Epix Pro 51 Sapphire

Thanks (first time with a garmin)

Within the weather widget, there should by 6 pages that you can scroll down through. The map view should be on the last (6th) page.

I only have 5 screens available in the weather widget on my Epix Pro.  No maps at all.  Is it only available in certain areas?

Same here and I solved doing this. 
1) update lasted software version. 
2) go to maps and download a topographic map. 
Watch rebooted with the map installation and boom new weathers maps and new activities. 
let me know if this work for you. 

Yup...  should've thought of that myself.  Just applied the update, and now it's there.  Thanks!