As it is recommended that you should wash your hair in every 2-3 days, or else in every 3-4 days if you are having dry texture of your hair. During winter season, you may reduce the number of hair washes so as to avoid eradication of natural oils from your hair.
Women often wash less in the winters which leads to build-up unwanted oil on the scalp. Therefore, it may lead to dandruff. If you want your hair to be healthy and strong, you may need to wash at least once in every three days.