you are not chilly when swimming in warm water. but when emerging from warm water on a warm summer day, you feel chilly if the wind is blowing. Explain

The human body utilizes the effect evaporation for cooling. Hence the water on the body surface make the skin to experience chilly as the wind blows to evaporate it. As the latent heat of vaporization is extracted from the body, it is cooler in the process. This is the same reason why perspiration cools the body as the sweat evaporate from the surface of the skin.