How long do bees hang around once the weather gets cold?

I live in the Pacific Northwest and I have bees coming into my house now that the temperatures are getting cold at night. How long before they disappear for the winter?How long do bees hang around once the weather gets cold?
Honey Bees stop flying when the temperature drops down into the 50s (F). They stay inside their hive in what is called a winter cluster which means they get into a big huddle. There is no point to flying outside of the hive as there are no flowers in bloom, hence no pollen or nectar is available. The colder the temperature the more compact the cluster becomes. he object of this clustering is to keep themselves warm, so warm that the temperature in the center of this cluster, where the Queen Bee stays, is kept at about 80 (F). The outer edge of the cluster is about 46 - 48 (F).On nice sunny winter days you can see honey bees flying a short distance out of the hive and then quickly returning. Sometimes if they go too far out or stay out too long they can get chilled and will not be able to fly back into the hive. The object of these short flights is to eliminate body waste.Bees appears around spring when the flower starts to bloom and it gets warmer.