The wind can increase the rate at which you lose heat, giving the perception that the temperature is colder than it is (wind chill factor).
The beauty of our women's windproof jackets is that they all use specialised fabrics to stop the wind penetrating whilst remaining lightweight. This means that if you are on the beach for the evening and a stiff breeze comes in off the sea you can keep it at bay without feeling suffocated or bulky in an insulated jacket.