A good pair of winter gloves will keep your hands warm, allowing you to cycle for longer. Your hands do not move very much whilst cycling so investing in a good pair of gloves suitable for a cold winter is well advised. Winter gloves have a longer cuff to prevent the cold touching your wrist.
There are different types of gloves, made from different materials. Many brands advise on the temperature range they are suited for. The gloves should be snug but not tight, a glove that is too tight will restrict the blood to the fingers. Wiggle customer reviews are also well worth reading.
Winter cycling gloves are designed to keep your hands warm, windproof gloves are especially good at this as they stop the winds chill from reaching your fingers. Many models incorporate a waterproof membrane to prevent the insulation layer getting wet, this is important as water carries the cold quickly. They are shaped so they're comfortable in the usual riding position and the fingers are usually pre-curved. If your riding position puts a lot of weight on your hands, choose gloves with padded palms, some even feature gel inserts for additional comfort and shock absorption. Alternatively, wear your summer cycling gloves underneath a slightly larger pair of insulated winter gloves.