Ubiquiti UniFI AC Mesh - fully weatherproof?

Addendum, can the Flex HD stand in complete rain?

Just insert it straight in. I sealed it with PU foam on my end.

I understand it goes into the access point. But what do you do before that? Flush-mounted box where the installation cable ends, install a keystone module, and from there use a patch cable to the access point?

Yes, the Flex HD can be used completely in the rain. It is fully outdoor compatible. All mine are mounted on the facade without weather protection. 3 x Flex HD, 1 x mesh pro
We have a ventilated facade. So we can do a lot... the simplest (and in my opinion also the best option) are keystone modules. We don’t need a box since everything runs behind the facade.
This is what it looks like for me. You can recognize the PU on the bracket.

I’m bringing this up again because I now know how I want to attach the thing to the facade. It’s been clarified that the FlexHD can withstand rain. But what about direct sunlight? Does anyone have experience that could be shared? It would hang on a south-facing facade with external temperatures possibly exceeding 40°C and corresponding sun exposure. I have used it indoors for a while now and the thing gets pretty warm….

Several have it outside on the aluminum facade. It gets significantly hotter than a "normal" one. No problem at all.

Thank you very much. Also full, direct midday sun?