There are more people of Irish descent in America than in Ireland, and Irish-Americans have brought their superstitions with them, to be adapted to life here, of course.
The reason I know these are Irish-American is because I heard all of them growing up in Ohio, which is definitely in America.
If you're going on a picnic tomorrow and you're worried about rain, hang a rosary in a tree overnight. You're guaranteed to have a sunny day tomorrow.
If you're trying to sell your house, bury a statue of St. Joseph in the yard. This is especially helpful in the soft housing market. To show how widespread this belief is, I have a 2011 Walter Drake catalog offering a St. Joseph statue for this purpose. The ad says to bury him facing the house, but the proper way is really to bury him upside down, preferably in the back yard.
In case this sounds irreverent, Irish-Americans who regularly attend church feel comfortable with heaven's denizens, and trust they'll understand.
If your ears are burning, someone's talking about you, and if your palm itches, you're going to get some money.
If a picture falls off the wall, someone is going to die, or else you can hope you didn't hang up the picture very well.
If you're walking with someone, and you come to a barrier like a pole, you have to walk around the pole together, both on the same side of it. Otherwise the two of you will have an argument. If you do each walk around a different side of the pole, you can mitigate the damage by saying, "Bread and butter."
Horseshoes hung up bring good luck. Here they have to be hung up with the curved side down, so the luck won't run out. In Ireland they're lucky only if they're found and not given. In ancient Ireland they were considered a sign of pure womanhood, and kept away witches, which is always a good thing.
Friday the 13th is unlucky because there were 13 people at the Last Supper and Christ died on a Friday. You can't avoid Friday the 13th, of course, but a little prayer and reflection couldn't hurt.
A black cat is unlucky, especially in the house. Don't blame me, cat lovers, I'm just reporting it.
If a funeral procession crosses you, it's bad luck. Hopefully not as bad as the guy the funeral is for.
Halloween, of course, is a Christian version of the Celtic feast of Samhain, when spirits of the dead returned to walk the earth. The ancient Irish left treats out for their deceased relatives, which no mortal would dare to touch. This may be the origin of trick-or-treat, with kids dressing up like ghosts and devils taking the place of those ancient spooks. When I was a child, my opinion was that being the recipient of the goodies was much more delightful than scary.
Many Irish-Americans believe in ghosts and superstitions about them. My great-grandmother always kept the closet doors closed, because if they were left open, the ghosts of all the relatives who had died would come out. In Ireland's ancient times, people were sometimes buried alive in church foundations to keep evil spirits away from the church. Great-grandmother's belief about the closets may be a vague recollection of that practice.
It's bad luck to look behind you when you're walking; there may be a ghost back there. If there is, you'd rather not know about it.
Ghosts are sometimes thought to be souls in purgatory, a remedial state in which they do penance for minor sins before they're admitted to heaven. If you see an unexplained light at night, it may be a soul on its way to its heavenly reward.
Irish-American superstitions aren't as rich and varied as the ones we left behind in Ireland generations ago; we rely on science and technology now. We're more sophisticated. Or are we? Wait, I think something is following me!
Picture from Wikimedia Commons