It's actually freezing out there (at times), and will probably only get colder, so here's a practical list for the month.
Maybe your garden shed needs a bit of a tidy up ready for next year. So wrap up warm, take a hot drink and venture out on a warmer day, to do a 'winter' clean. You can include a clean up of your garden equipment as part of this
Go potty. Again, an inside job. Take time to spruce up those pots you may have lying around - a lick of paint on a pot can be as good as buying a new one. Maybe a pot just needs a good clean? Again, all done now ready for Spring, when you will have plenty of garden jobs to do!
I'm no weatherman, but should we get some snowfall and its heavy, make sure you brush it off shrubs and small tress. This will help to maintain their shape - something the weight of snow can ruin!
Reading time - if it's too cold to be in the garden, then emerse yourself in reading about your garden. Look for inspiration for 18 in books, magazines and websites
It's a bit late now to plant a winter garden but it is a great time to plan one for next year. Take a look at your garden and spot areas where a 'winter garden' would be a treat for the eye in the colder months. The brightly coloured stems of a Cornus look fab in winter as do any grasses. I've planted both in 2 of my recent Plan B gardens