Wedding attire help

[PiobBear]

The wedding is at 4 PM so technically wouldn't the PC be too much? I fear that I will be way overdressed.

Regardless of the time, unless specified otherwise a PC would be way too much; as inappropriate and out-of-place as wearing a full wetsuit with tanks, mask, & fins.
What does the invitation say? Very many formal weddings around here start before six; however nobody outside of the wedding party is expected to dress black tie. After six, not all weddings are formal. A less formal jacket & tie like the Argyll would be fine (unless of course it's an informal garden or beach wedding, in which case loose the coat). It's their wedding; dress according to your host's expectations; when in doubt, ask. That's why you're called a "guest".

[davedove]

What does the invitation say? ....It's their wedding; dress according to your host's expectations; when in doubt, ask. That's why you're called a "guest".

This is the best overall advice. We can debate the rules all day. We have to remember, however, that these rules were developed by aristocrats who had the money for all these different levels of dress. A lot of today's society doesn't even know these rules, let alone follow them.

It's good to know the rules, but the most important rule is to follow the lead of the hosts. To dress at a certain level because it's the "proper" way to dress, even though the hosts have set a different level of dress, is insulting the hosts, as you are putting yourself above them because you "know better".