For my Mil's funeral I wore smart black trousers, flat black shoes, I can't remember which blouse but it will have been with sleeves and a 3/4 coat in a grey/blackish tweedy stuff. Something similar at fils funeral.
I have absolutely no idea what I wore to mums funeral. I got through it, that was enough.
Both in winter, so a coat is vital.
There is usually a lot of standing around waiting for the coffin to arrive and afterwards talking to everyone.
Personally I don't think it matters much what you wear. No arse or cleavage on display, usually muted colours (grey black navy). Be warm enough and wear shoes that are comfy.
Funerals are bad enough without thinking your feet are going to drop off by the end of the service.