Snow isn't the only thing that can lead to closures
We went a few years ago with a large gang of people around the Columbus Day weekend, and while I don't think it had snowed recently, nights were cold and I believe as a result of freezing rains stuff above treeline had a nice verglas (there's a word I like to squeeze into conversation and don't get to very often ;-)). That was enough for the rangers to close all above-treeline routes and they seemed fairly serious about the closures being a hard-and-fast rule vs. a recommendation. We didn't tempt them too much and since some people in our party were dying by the time we got to the treeline (we had a very mixed group with probably 2:1 differential between the fastest people and the slowest people), we poked a bit further and turned around.
That said, even with the disappointment of not being able to get above treeline, the weather during the day was gorgeous, the foliage was amazing and in general it was a fabulous weekend, even including my failed attempts to keep my wife from stalking a moose cow with a calf (fortunately, the cow was feeling generous and didn't let her have it).
I'd still highly recommend it, it was really a marvelous time of year to be up there, even if stuff above treeline happens to be closed.