How long is uncorked red wine good?
A day or two. Longer if you cover the top of the bottle.
You don’t want to just cork it. It’ll maintain it’s drinkability far better if you’ll vacuum it with a pump, readily found at most liquor or grocery stores. I think they’re about $10.00 or so US and well worth it.
I second the vacuum pump lieu.
I have a hand pump, I’ve corked a bottle with it and it’s still been good 5-7 days later.
MtM