It's possible to use foundation during the winter months as long as the objective is for a more uniform or radiant complexion.
The most important thing to remember is not to change the shade of your foundation. If you change the color of your foundation, you necessarily end up with a complexion that is too pale or too dark for your natural skin tone – which is not the effect you're after! Opt for the exact shade as your own skin, and avoid going any darker which, contrary to popular opinion, does not give you a sun-kissed complexion. Quite the opposite, using a foundation that is too dark for your skin will accentuate signs of aging such as lines, wrinkles and under-eye circles.
Even more important than the right shade is choosing a foundation with a UV filter. In fact, more than the "flawless" effect that all women are after, your foundation should also protect your skin against the cold and the sun's rays. At least, it should provide more protection than if you weren't wearing any makeup!
A foundation that matches your skin tone (with built-in UV protection) will be your ally this winter. And, don't forget – never change the color of your foundation!