From the top floor of my city’s downtown library, through the thick-paned glass windows, I can see the high-rise office buildings and apartments of the surrounding cityscape, and I can also see a small apiary — three rooftop beehives — that are being kept on the library’s balcony.
Temperatures have dropped well below freezing, and the first snow has already fallen. The drones, or male bees, are lying dead on the ground around the beehives. But through the glass sides of the hive boxes I can see the worker bees inside. With stores of honey laid up, clustered together for warmth, moving and dancing their tiny bodies to generate heat, they are ready to survive the cold snowy winter ahead.
Rooftop beehives like these are becoming more and more common, from the West Coast to the East. The San Francisco Beekeeper’s Association increased its numbers from 50 members in 2000 to more than 400 members in 2010.[i]  Beekeeping was legalized in New York City in 2010, where it has recently surged in popularity.[ii]  Bees raised in city apiaries are often healthier and more productive than their rural and suburban counterparts because they are exposed to fewer pesticides. But hobbyist beekeeping is on the rise everywhere, not just in urban centers. Backyard apiarists are attracted by the promise of rich honey to eat and bee pollen and beeswax for herbal remedies, not to mention the benefits of pollination to their fruit trees and vegetable gardens, and the chance to reconnect with the outdoors and make friends with nature’s unsung heroes.
And the timing for an increase in beekeeping couldn’t be better. The woes of Colony Collapse Disorder (CCD) are widespread, and last winter up to 70 percent  of bees did not survive in some parts of the country. Loss of bee colonies is bad news for U.S. agriculture; bees provide the pollination for more than 80 percent of all the fruit, vegetable, and flowering plants in existence![iii]  Some crops are almost singularly dependent on honeybees for population.
Backyard beekeepers are answering the call to action, but one of the biggest worries facing urban and rural beekeepers alike this: How do you get your honeybees to survive—and thrive—through the winter? As apiculture experts Adrian and Claire Waring write, “…The main testing period for colony survival is the winter. It is the season that intensifies … testing the bees’ ability to conserve food, stay confined, possibly for long periods, and then develop in the spring.”[iv]  This article goes beyond the basics of beekeeping  to cover the essentials for taking excellent care of your bees through the wintertime.
How Bees Prepare for Wintertime
As they prepare for winter, bees use propolis (a resinous mixture collected from trees and plants) to cover cracks and seal holes in the hive so that it’s completely wind-proof and weatherproof.
Another important task to prepare for winter involves population control. Drones, or male bees, serve only one function in a beehive: mating. They cannot sting, defend the hive, collect pollen and nectar, and care for larvae as female worker bees can. In the winter, they are nothing to the hive but more mouths to feed, and so they are given the boot in the fall. Without the warmth and resources of the hive, they quickly die. So don’t panic if you see dead bees laying on the ground around your hive as autumn hits; they’re probably all drones, and this is a completely normal part of the yearly life cycle of a healthy beehive.
Bees are cold-blooded creatures that are immobilized when their body temperatures drop below 45°F. They combat the cold by a phenomenon called clustering. When temperatures drop below about 55°F, all the bees in a hive begin huddling together in a group called a cluster, with the queen protected from the cold in the middle. The worker bees dance and move their bodies to generate heat and to share it with their sisters. The lower the temperature drops, the tighter the cluster will be. Clustering is remarkably effective for self-regulation of a hive’s temperature; even on the coldest winter days, bees usually maintain a temperature of around 94°F in the center of the cluster.[v] 
Bees aren’t completely dormant all winter; on warm days they leave the hive to expel waste, and aside from a two- to three-week hiatus in early winter, the queen continues to lay brood all winter long. But since foraging is limited in the wintertime, bees subsist on the honey stores they’ve built up all summer long. Huddling into clusters and limiting movement helps the bees to conserve their precious stores of honey so that they’ll last until spring.
Helping Your Bees Through the Winter
The most important preparation for winter happens months ahead of time. Summer brooding—laying and incubating eggs—is essential, because the bigger the hive is, the better chance it has of surviving the winter. There are several reasons for this. Bees can’t use their movement to heat the entire hive, just the cluster and the area surrounding it. If the cluster is too small, incubating brood will be left in the cold to die. And if a cluster is too small, it just won’t be able to generate the necessary heat to stay alive.
That’s why it’s essential to closely monitor your hive’s population all summer. If the hive is too small, you can requeen, or replace the queen. Younger queens lay more brood, increasing population before winter. If you requeen, it’s important to do it in the spring or summer, not the late fall. If the new queen is rejected by the colony, you’ll need to try again and you don’t want to leave your hive without a queen as winter begins. An added benefit to replacing the queen is that colonies with new queens don’t swarm, so you won’t have to worry about your hive swarming or leaving before winter.
When you set up your apiary, make sure you establish your bees in a place where they can winter well. Choose a spot that’s out of the wind (or position some hay bales or build a fence for a windblock), and a place where hives can face south and catch the sun. Don’t move bees into a shed or outbuilding because they’ll consume more of their food stores and then they might not have enough to last the winter.[vi]  As winter approaches, seal up any cracks or leaks on the outside of the hives (the bees will take care of the inside).
Keep Mice From Invading
Mice begin their preparations for winter early, so you should begin your preparations for mice early. For a mouse mice, a beehive is a cozy place to spend the winter. It’ll move in, build a nest, and cause your colony to abscond, or abandon the hive. In warm weather bees can hold their own against a mouse, stinging it to death when it enters the hive. But in wintertime on cold nights when bees are clustered together, a mouse can sneak in. The easiest way to prevent this is to place a mouse guard over the entrance. Its holes are big enough to allow bees to pass through, but too small for mice. Metal ones are far superior to wooden ones, which mice can easily chew through. If you’re putting a mouse guard on late in the year, be sure to check your hive first and make sure a mouse hasn’t already moved in.
To Wrap or Not to Wrap?
Wrapping beehives to insulate them from the cold used to be standard practice. But now most beekeepers agree that it’s unnecessary unless you live in a place with really cold, harsh winters. Bees are so good at creating their own heat that hives can actually get too hot!
If you do decide to wrap your hives, use a warm cloth and cover the hive with a tarp to waterproof it. Never close off the hive entirely; the entrances to the hive should always be accessible. Not only do hives need ventilation to let moisture and carbon dioxide out, but bees need access to the outside world. On warm winter days (above 50°F), bees leave the hive to expel waste (to defecate, and to carry out the bodies of dead bees) and to forage.
A good compromise between wrapping hives and leaving them unprotected is an insulation board. A top insulation board helps hold heat in the hive without overheating or trapping in the bees. Another option is to paint your beehives black to help them absorb more heat from the sun.
If you’re not sure what measures to take, the only way to know for sure is to ask local beekeepers. There are no one-size-fits-all rules for beekeeping; every place is unique in terms of latitude, elevation, humidity and weather patterns. To be successful on your apiculture journey, there’s no substitute for making contact with some local folks who have been in the business longer than you have. They can tell you everything you need to know.
Food to Last the Winter
When you harvest your honey in the summertime, make sure you leave enough to keep your bees alive all winter. The amount will vary depending on how long your winter is, but generally 60 to 70 pounds of honey is required. You can estimate about 5 pounds of honey per deep frame, so you’ll need 12-14 frames.[vii]  If you don’t have enough honey, you’ll need to supplement the bees’ diet with sugar syrup.
Monitor your bees throughout the winter; make sure the entrances to the hive stay clear from snow and dead bees, and keep track of how much honey they’re consuming. Don’t open the hive to do this; it’s hard work for them to maintain the proper temperature inside! Instead, you can heft the hive frequently and take note if it starts to feel very light (indicating that the honey inside is consumed). Also, bees begin the winter at the bottom of the hive, eat all the honey there, and work their way up the hive, so if you peek inside and they’re clustering near the top that’s another indication that they’re almost out of food and you’ll need to supplement their diet.[viii] 
You can find detailed instructions and information on wintertime feeders, recipes for sugar syrup and pollen patties, top insulating boards, the proper way to wrap hives, and everything else you need to know in books like Kim Flottum’s Better Beekeeping, Richard E. Bonney’s Beekeeping: A Practical Guide and Storey’s Guide to Keeping Honey Bees. And don’t underestimate the value of experienced local beekeepers! Join your local apiculture society and make contact with others who have already successfully gotten their bees to weather the winter. They’ll probably have some valuable tricks up the sleeves of their parkas.
Belknap, Cindy. The Complete Guide to Beekeeping for Fun & Profit: Everything You Need to Know Explained Simply. Ocala, Florida: Atlantic Publishing Group, 2010.
Bonney, Richard E. Beekeeping: A Practical Guide. Pownal, Vermont: Storey Books, 1993.
Kandel, Shaina. “The Ins and Outs of Urban Beekeeping.” Meeting of the Minds. January 14, 2014, accessed 11/14/2014, < https://cityminded.org/buzzing-rooftops-ins-outs-urban-beekeeping-10216>.
Sanford, Malcolm T. and Richard E. Bonney. Storey’s Guide to Keeping Honey Bees. North Adams, Massachusetts: Storey Publishing, 2010.
Valentine, Katie. “How a Rise in Backyard Beekeeping Can Help Teach City-Dwellers About Climate Change.” Climate Progress. June 4, 2014, accessed 11/14/2014, <https://thinkprogress.org/climate/2014/06/04/3437980/city-bees-and-climate-change/>.
Waring, Adrian and Claire. Teach Yourself Beekeeping. Blacklick, Ohio: McGraw Hill, 2006.
[i]  Kandel, “Buzzing Rooftops: The Ins and Outs of Urban Beekeeping.”
[ii]  Valentine, “How a Rise in Backyard Beekeeping Can Help Teach City-Dwellers About Climate Change.”
[iii]  Belknap, 16.
[iv]  Waring, 103.
[v]  Belknap, 265
[vi]  Bonney, 111.
[vii]  Bonney, 110-111.
[viii]  Bonney, 115.