The beautiful Anna Hummingbirds that come to our area usually arrive when all the Rufus hummers have migrated in about October. It is recommended that you keep your feeders up and in a place where it is easy to observe who visits. My feeder is on the North window that I look out when using the computer. If it snows, I can open the window to reach outside and wash and refill the feeder without getting too cold or wet.
The female Anna looks similiar to the Rufus female. She will be a tad bigger with an all gray (not cream with brownish) tummy. The male Anna is so stunning. In the fading light of winter his head can look black instead of the bright fuchsia pink until he turns to catch the light.
In our area, there are still flowers when they move back. The hardy fuchsias are still blooming and the beautiful pink nerines will last until there have been some really hard frosts.
The most helpful thing you can do, of course, is to keep a feeder with FRESH solution (changed at least every 4 days regardless of how cold it is). I make a cup and put 1/3 of it in the feeder every 4 days. I have 2 females and one male this year.
You may think you don't have these tiny creatures, but feed them in a place you can monitor and they will come. It helps to establish your routine in September or October rather than later.