Hi Chris,
You might find this site useful.
http://darksitefinder.com/map/
Its also not quite as simple as "dark". Transparency is also important. Where I observe, the sky in Winter is very dark but also quite still. Transparency is very good, when its not snowing, raining or foggy...
I can see the Sigma Octanis asterism visually on a regular basis even with my 50+ year old eyes. I often get a Milky way over 160 degrees and can easily follow branching dust lanes. Omega Centauri is an easy naked eye object.
Not much to complain about
