I've been successful gardening into the fall & winter here in NW WA state........but I confess, I'm not much into it when it really gets rainy, dark early and I'm having to be pulled from in front of the wood stove to go outside.
I do plant lots of crops that I leave on the vine or in the ground until it looks like we're going to get the first real frost and then I harvest like crazy and store things in the garage.
I've got a late planting of spinach and lettuces here now, that will probably take us through Thanksgiving.......and squash of all kinds, some mystery ones even, that will be on the vine until the first freeze. Tomatoes I leave out in the garden too, or pick some green ones as time goes by, and let them ripen up inside.
I can swing some radishes if I put them in up by the house, to keep them a tad warmer.........but that's about it for my off season gardening. Not so much a limitation from the gardens' perspective, but the gardeners!!!

I'm a fair weather gardener when it comes right down to it!!