I’m not sure what the weather is like in your area, but out here on the West coast it is another day of rain 
With the change of the season to fall, I start to think about how I can get a few more days of nice weather on the deck and what I can do to extend the season. A patio heater or an outside fireplace are good additions. Also, an awning and or covered deck is a nice thing to have. So at this time of year I start the planning process of how I would like to improve my deck for the fall and summer.
Now is a good time to think about your summer experience on your deck and what you would like to change. It might be something simple like adding a thermometer to the deck so you can check the temperature. Or it might be a bit bigger like re-staining the deck. Or even bigger like rebuilding the deck. Either way, now is a good time to start planning for what you would like to do during the winter months.
Some things you might be able to do now or you can be prepared to do when you have a nice sunny afternoon. Head down to your local hardware store and look for the right thermometer, mabye even pick one up on sale. Or if you project is bigger like building a new deck you can start planning and making decisions on what you want. If you are looking at building a new deck I recommend you look at purchasing deck plan software.
If you are designing your own deck, deck building software is good investment of your time and money. The software can help you design and visualize your new deck. Good packages will also create a part lists and show you where you need to include the supports. Some packages will include plans and you can use these as a starting point. Depending on the package you purchase some are more complex than others. So now is a good time to get the deck design software and start learning the program. This way you will have a complete plan by the time you are ready to start building in the spring.