Like @MommaJ I keep mine in the fridge. No tears.
Fill your mouth completely with water (full, give yourself chipmunk cheeks full of water) while you cut them. Don’t remember where I learned this, but it works for me.
Well, that’s a pretty hilarious image. 
I have my daughters chop up the onions. works great for me.
My eyes are so sensitive that they’re tearing up just reading about cutting onions.
I have always had luck with burning a candle.
And this is hopeful: http://www.latimes.com/food/sns-dailymeal-1863539-healthy-eating-tearless-onions-121917-20171219-story,amp.html
I have to say that when I first saw this thread, I read the title as “trick not to cry while reading the Onion.” :))
Wearing glasses does not help. Onion variety matters- we refrigerate sweet onions (climate hot and humid) and that may be the difference. I dislike the thought of spending too much time wasting onion parts by dissecting them to lose parts per post #25 link. Post #26 has a link with a 10 ways link that lists a lot of already posted methods, plus some.
Post 26 is efficient . And as for the post above it, you don’t have to throw away the center part of the onion, you just can. But the cost of the center part of an onion is rather minuscule so it’s not a big deal either way.
This is a thread about how to stop crying while you’re cutting onions. The option to cut the center out prior to cutting the rest of the onion accomplishes that. Whether or not you want to keep the center of the onion is a personal decision for the few cents it’s worth in time and tears.
I always used to cry, a lot, when cutting onions. There were recipes I’d avoid purely for that reason. But the other day DH had put the onions in the fridge and I cut one up quickly (chopped vs minced) – no tears! I think it was the onion being cold and not having to cut it up much. But I love all the tips here!
Yes, refrigerating the onion does reduce my tearing so I don’t tear, especially if I take my glasses off and stand by an open window so vapors can vent.
You can buy onions in the frozen veggie section for about $1. Use what you need for the recipe, put the rest back in the freezer for another day.
It’s a problem, but I really don’t like to keep onions in the fridge because the temperature and humidity will affect freshness and texture. I’ve tried some of the other suggestions without seeing much difference. Maybe it’s just me.