It's a common complaint this time of year.  My hair is full of static, has no volume and won't perform the way it used to.
Check out this HOT TIP to maintain your look through the dry winter months.  A misconception is that conditioner ways the hair down and therefore many people eliminate this important step.
A helpful tool is a leave in conditioner that is lightweight enough that it won't weigh the hair down but will give your hair the moisture it needs.
A couple of my favorites are Redken's Clear Moisture Polish Prep and Color Extend Total Recharge.  Both are lightweight sprays that can be left in the hair without adding weight.  The benefit is that your hair will have the extra moisture needed right now and your styling products can be applied directly on top of these treatments.  Think of it as spackling before you paint - the porous areas of the hair shaft are filled in and you have a smooth surface to apply your styling product to.
Give it a try and see how great your hair performs even in the middle of the gray days of winter!

Blessings