Exposure to cold can cause injury or serious illness such as frostbite or hypothermia. The likelihood of injury or illness depends on factors such as physical activity, clothing, wind, humidity, working and living conditions, and a person's age and state of health.
What constitutes extreme cold and its effect varies across different areas of the United States. In areas unaccustomed to winter weather, near freezing temperatures are considered "extreme cold." Freezing temperatures can cause severe damage to citrus fruit crops and other vegetation. Pipes may freeze and burst in homes that are poorly insulated or without heat.