Winter can be a difficult time of year for a lot of people. The cold and lack of sunshine can bring on Seasonal Affective Disorder or SAD. It also can effect those with Arthritis or muscular and other emotional disorders.
As for me, I have arthritis and Fibromyalgia. These affect my creative abilities and ability to actually physically do the creating. This is the worst symptoms I have had in many years and am trying to get past the depression that results. All I want to do at the moment is go into a cave and hibernate until the sun returns. In the mean time, I also go through a period of being clumsy and off balance.
I really admire those that can call on their creative muses to lead them into an artistic adventure of beauty and balance.