By Gazkir
United Kingdom 
To plant out runner beans we wait until we expect no more Frost. In Gardening Folk lore is there a specific date "Bean Day is May the ?"
17 May, 2016
Answers
In the north of Scotland we don't plant out until risk of frost has passed - we don't grow runner beans :-(((( Climbing beans are quite hardy.
17 May, 2016
I have dwarf beans planted out already - we have had very little frost all winter and none at all for ages.
17 May, 2016
Our runners were planted the weekend before last, after a period of hardening off.
17 May, 2016
Not so far as I know - all I can tell you is, the last expected frost date in the southern half of the country is the last day of May. Even that gets broken some years, we've had frost in London on 4th June before, but it is rare. But I used to plant mine outside beginning of the last week of May (in West London) provided I'd already hardened them off beforehand.
17 May, 2016