How many plants are you talking? If its just a few you can set them out and be prepared to cover them if it looks like frost. Keep a close watch on the weather.
One can never tell when the last frost is going to be this year. You can search the archives and find an average last frost date, but there is no guarantee it won't freeze after that date.
Gardening at 5000 feet elevation, zone 4/5 Northern Utah, Frost free from May 25 to September 8 +/-