I obtained my bees after most of the nectar flow so are needing all the help they can get in obtaining stores to get themselves through the winter. The bees are still flying on some days and are accessing the sugar syrup I offer them. Is there some time for certain that I should stop feeding them syrup?
Congratulations on getting your first bees!
Once daytime temperatures drop below 57° F, stop feeding liquid syrup and switch to a solid sugar board.
Liquid syrup puts too much moisture in the colony, and the bees are unable to evaporate the excess moisture to ensure long-term storage of the syrup.
The final chapter of the Honey Bee Health Coalition publication, Best Management Practices for Hive Health: A guide for beekeepers, covers honey bee nutrition. They suggest stopping liquid feed when it reaches 50° F during the day.