It might not be a great thought, having to venture out into the cold outdoors this month - but rest assured there are only a few jobs to get on with whilst you enjoy the Christmas period.
Frost Protection
Keep on top of sweeping your paths and reducing slippery surfaces to prevent any accidents. You may also want to cover surfaces with mats or grit and improve drainage to prevent surfaces from becoming wet before they freeze. If you haven't already, you should check heaters in your greenhouse and insulate the inside to protect plants from the colder nights.

If you have any water features, it might be a good idea to insulate pipes in case a particularly cold winter comes. You should also take the time to throw a few tennis balls onto the surface of your pond, as they can prevent the surface from completely freezing over in a frost and keep air holes for fish. This can be deadly for them, so if it does happen hold a pan of boiling water over the ice but avoid cracking it as this will disturb the fish. Whilst you're by your pond, rake out any fallen leaves to prevent algae growth.

Heavy snow can also be a problem for the garden. Shake or knock branches with a broom to prevent damage from the weight of built up snow during particularly bad bursts of winter weather.
Pruning
You can now begin to prune trees and shrubs, with the exception of prunus species, evergreen and tender plants. It might be early, and the majority of your pruning will be done in the next few months, but a little bit here and there will save you a lot of time in the new year. Doing this now while the branches are still bare will make it a lot easier to see what you're doing.

Lawn Maintenance
It's tempting to neglect the lawn at this time of year, and there isn't much to do, but the odd job here and there will leave your winter garden still looking fresh and tidy. Don't be surprised if your lawn grows a little and be prepared to trim if it starts to look untidy. Whilst the leaves are still falling, keep on top of removal as this will keep light and moisture reaching the grass and leave it looking healthier. Avoid walking on frozen lawns and damaging grass - if you absolutely must walk across your lawn, stepping stones are a great attractive way of allowing this whilst protecting the lawn.
Wildlife
Keep leaving food out for the birds with fresh water. Make sure you don't neglect these as they can quickly become frozen or full of debris in harsh weather, keep them clean and free of ice. Little piles of wood can also help out our wildlife friends as they become crucial shelter or nutrition for all kinds of creatures in bad weather.

Harvest
Now is the time to harvest your veg. As you lift it, check for any signs of rot and remove afflicted produce before it spreads to the rest of your crop. The best thing is you can harvest just in time for Christmas and enjoy truly fresh veg such as cabbage, sprouts and root crops planted earlier that year, as part of your festive meal.