How late for grayling

[Rockyman]

I'm just wondering how late people continue to fish for grayling? I typically don't go out much past Thanksgiving because I find that my stream starts to really drop off by the end of September. I think that's because the fish have moved farther downstream. However, if you can find a good wintering pool is it worthwhile fishing right up until the season closes (or until the river ices over - whatever comes first)?

Thanks for any thoughts on this.