Your skincare routine may be perfectly suited to your skin type—but that doesn’t necessarily mean it will work equally well all year round. The moisturizer that keeps your skin comfortable in January may feel heavy and greasy in July. A lightweight summer cleanser may leave your skin feeling tight when winter arrives. Even if your skin type stays the same, your environment changes constantly, and those changes can influence hydration, oil production, irritation, sensitivity, and the overall condition of your skin.