The lake I fish for kokanee is a high elevation lake. We normally target them up there into mid September. When the spawners outnumber the keepers we call it a season. The lake is closed during the winter months, and even if it was open your looking at a 10 mile trek in by either snowshoes, cross-country skis, or snowmobile. Then, if you make it up there, you'd have to shovel around 8' of snow off the ice.
I work on lures during the winter...thumbsup