Our rule of thumb in this area is not to put anything in the ground until the night temps stay at 55 - except for cold weather plants like greens, potatoes, cabbage, lettuce, etc. Corn and beans, tomatoes, peppers, eggplants, okra, etc. love warm weather. Corn won't come up if it's cold and if it has to wait long for warm weather, it will rot in the ground. It just doesn't pay to rush mother nature.
Also check with your county extension agent (or whatever they're called in your area). They're there to help you. Check to see if there are any master gardeners in your area. We have a group that comes to our farmers' market 2 times a month. They are a wealth of information and if they befriend you, a great place for plants.
Edited because I think of things after I hit the submit button. DUH
Well, it was nice and warm when we planted the corn and beans, we just got that cold spike. Temps for the next 10 days are all in the high 40's. In fact, I just moved 10 day old chicken chicks outside yesterday and went through the night without any issue. If they can do it, certainly corn can, right?
:/ I've been carting my tomato plants in and out for days now - one even has flowers on it!
I need to get them planted out soon, I'm tired of this in and out stuff.
After our big freeze I thought all was lost - however, my bok choy and radishes popped out a couple of days ago, they look pretty good! My onions are still going strong and I think I have a couple of carrots popping out (normally take about 2 weeks but with the cold we had its been almost 3 weeks now)