Too few opportunities to dress like a regular human leads to way too much time thinking about what to wear. So here are my Christmas Eve mass choices. What say you, red pants or green pants? Anything that you love or hate?
The red pants look to me like Nantucket red rather than Christmas red. That said, red and green, especially deep red and muted green, are a splendid colour combination.
I'd go for the second of your choices if I were you. My personal choice, from the clothes I have, would be a deep red blazer, Black Watch trousers, and any red and green tartan tie (MacFarlane or Stewart, say).
Thanks for this information @OldMetairie . Brick Red might work out fine, although it still has summery associations. A very dark red shading into maroon/burgundy would be more Christmasy. These are just guesses, since I can't actually see the item in question. Also light matters tremendously -- what looks like an acceptably dark red indoors might look very bright in sunlight. Hard to tell!
If you really want to wear the red trousers, put it on and ask a few friends. See if they think it is fine or if it is too bright for winter.