I’m in Central VA, we do get temps down into the 20s fairly frequently and in the teens occasionally. My horses live out with access to shelter. Most years, I do a combination of a trace and a blanket clip, taking a little more hair than a trace, less than a blanket.
I only put turn out rugs on if the weather is REALLY foul - wet snow or sleet. Last winter I didn’t rug them at all because the winter was mild. I use mid weight turnouts.
I worked for a riding school for many years that handled all the schoolies this way - blanket clips, and turnout rugs only in the foulest weather.
This has worked well for me for years. However, my horses are both easy keepers and tend to get fat on free choice hay, and they are only in light work. This method probably wouldn’t be as successful with hard keepers or horses who were eating concentrates because of their work load.
As in all things horse, YMMV.