I bought two of the 1 season quilts when they were on sale this past fall (a long one for me and a regular one for my daughter). Since I live in FL they are really more like 3.97 season quilts
I got to test it out last weekend when the temps dropped to about 40 or maybe a little below. I had on some long underwear and ended up being too warm and had to vent. I'm pretty sure that if I wear my long underwear and another layer or two I can get it down to freezing or a smidge below.
I'm very happy with this quilt and am confident that it will work for almost the entire year in FL.