The hardest time of the year for Bees is Winter. Not many flowers, cold temperatures, rain, and/or snow, ….. This is the most likely time for Bee colonies to die.
I as a beekeeper try to help them out as much as I can.
You can do the same by planting flowers and trees that flower during this time of they Year. I found this article about it. It is from the UK, but the same principles apply of course here in the US. Plant Winter Flowers
A Jar of Honey San Jose 