what is the best climbing yellow rose that is fragrent for zone 4?

Answer 1

'Golden Showers' Climbing Rose Zone 4 Ht 6-10ft. 1956 AARS winner
http://www.horsfordnursery.com/new/plants/roses/html/roses2.html
A 6-10ft. free blooming, wonderfully fragrant yellow climber that's considered one the best of its kind.

This site list Golden Showers as hardy even to zone 3
http://springhillnursery.com/product.asp?pn=05512

P.S. The first two roses submitted by the second answerer are not hardy in zone 4, & the third selection mentioned needs protection in your zone... That's why I didn't choose it.

Answer 2

Here is a helpful site. Just select the rose color and it will give you a large list of roses of that color, bush or climber, and for what zone.
http://www.rosefile.com/RosePages/byColor.html

David Austin Roses for Z 4 & 5
http://www.davidaustinroses.com/american/Advanced.asp?PageId=2063

Hope these help