The 90% first frost date in our area is early October. But, of course, this is an exceptional year and our first frost was on September 22.
We have gobs of green tomatoes and lots of Thai hot peppers that aren't ripe yet, so we covered most of important stuff in plastic.
Bill also built me a cold frame for the top of a couple of raised beds. I started broccoli and beets in here a few weeks ago and recently added some lettuce and radishes. We'll see how it works! Hopefully we'll have some homegrown lettuce for tacos throughout the winter.