This really cold weather always dries skin and nails out, just use a good moistuiser on your face, good handcream which you need to rub into your nails and cuticles. Your body needs sunshine to activate vitamin D which in turn aids absorption of calcium so get as much sunlight as you can.
My nails and skin are actually really good and I do look after them but at this time of year my hands are dry, my nails split and my face looks dry too. Soon as the spring comes you'll notice they improve greatly.
By the way I use Liz Earle moisturiser and L'occitane handcream which is the best ever!