I must admit I'm scandalized with this thread.
The fact is, Catholics ought to know that when the liturgical color of the day is red, because it's the feast day of a Catholic Martyr, it is then not only appropriate, but DESIRABLE for all the ladies to wear red. In fact, it shows lack of community and pride (if not merely ignorance) for a lady to wear any other color instead.
The same goes for all the other liturgical colors in the Roman Rite:
White
Green
Purple
Rose
Gold
Black
(Note: no yellow, blue, orange, purple, turquoise, rust or brown, but most women don't wear orange anyway; Byzantine and Russian Orthodox use blues, purple, orange or rust sometimes)
Time was, before the infamous Vatican II, when women knew that, they would keep the parish calendar near their dressing room, so they could check the color of the day before they selected their outfit for Mass. They would also plan a week or two ahead so they were sure to have the colors they need for particular Masses, by having the clothes laundered, mended or cleaned on time, relying on their calendar to help them plan ahead.
What's the point?
When the priest enters the sanctuary dressed in his liturgical colors, he is transported with joy to see the congregation adorned with the same color that he is wearing himself. And the women in the pews have assisted with the silent acclamation that the Church is One.
Up to this post, everyone has been contemplating their belly buttons, musing about how red suggests this, that or the other thing. HOGWASH! Red suggests MARTYRDOM when worn to Mass. Make no mistake about it!
That goes for red hats, red scarves, red gloves, red belts, red overcoats, red stockings, red lipstick, red hair ribbons, red purses, and red shoes, too. They all suggest MARTYRDOM, in honor of the saint of the day.
Exception: fingernails. It has always been considered proper for women to use only natural color for fingernails, if any color at all.
That applies to women. Do not presume it applies to men. It doesn't. Men are perfectly proper wearing a black suit and a white shirt every day of the year. Recall the old canard, regarding automobile colors. Henry Ford is quoted saying, "You can have any color you want, so long as it's black." Boring? Not boring, standard. Of course, various orders have habits for the monks and/or priests, but that's for religious, and we're talking about laity here.