Winter skin dry summer skin oil is generally associated with temperature, mixed skin type, lack of micronutrients and other factors, you should seek medical attention to identify the cause. 1. Temperature: winter temperature is low, the speed of skin oil secretion decreased dramatically, at the same time due to air conditioning heating and other factors make the skin water loss, the skin will feel very dry. In summer, the temperature is high, the skin secretion is strong, will lead to oil secretion speed, so the summer skin will be oil. 2. Mixed skin: winter skin dry summer skin oil belongs to the mixed skin, generally this skin is easy to dry cheeks but the T-zone oil, especially in the fall and winter seasons, the faster the loss of moisture, the cheeks will be more dry, and the skin in the case of severe dehydration or even peeling will secrete more oil, resulting in the summer the skin will become more oily. 3. Lack of trace elements: trace elements are important elements needed for physical development, if the lack of vitamin A and vitamin B2 will lead to dry skin, while the lack of vitamin B6 and vitamin C will lead to greasy skin. Dry skin in winter and oily skin in summer patients should seek medical attention to find out the specific causes of the disease and then actively deal with, so as not to delay the condition.