Most of us think of black suits when we think about funeral attire. Black is traditional, but it is no longer the only appropriate color to wear to a visitation and funeral.
My suggestion would be to wear “church” clothes. If you wouldn’t feel 100% comfortable wearing it in a church, it’s probably not what you want to wear to a funeral.
Dress respectfully. I would err on the conservative side. Wear a suit and tie if you are a man and a conservative outfit for a woman. For your children, once again I would say church clothes or one of their better outfits.
If you don’t’ own a suit, make do with the nicer clothes you do have. How you dress is not as important as your presence for the family.
SIDE NOTE: If you are working and just have time to pop in from work, come in your work clothes (example: uniform, scrubs, etc. – use your best judgement). Everyone will understand and the family will appreciate your presence.