55 is a yes without thinking twice for me.
Because of how windy and weird the weather can be in Oklahoma, there are typically more important factors at play than the temp. That being said, if its sunny and there is little wind (< 10mph), anything above 35 or so is a go for me - I’m pretty warm natured so walking the course at that temp, when properly clothed, isn’t bad.
If there’s a typical 10 mph wind and isn’t too overcast, 38-40+ works for me. If it’s 15-20+ mph wind and wet/overcast, probably needs to be in the high 40s/50s.
(Since I’ve started typing this others have commented on wind/sun as being major factors - totally agree and am too lazy to go back and edit this post to contemplate the fact others have already said this).