The heat index provides information about how hot it feels outside in the shade. It is a measure of the air temperature in relation to the relative humidity for a particular day.

The National Weather Service lists a heat index each day in the newspaper to alert people of the risk for a heat-related illness. Direct exposure to the sun can increase the risk for a heat-related illness on days when the heat index is high. Babies, older adults, or anyone with a health condition may have more risk of problems with the heat because of their age and general health.

A heat index of:

• 80 A?F (27 A?C) to 89 A?F (32 A?C) may cause fatigue.
• 90 A?F (32 A?C) to 104 A?F (40 A?C) may cause heat cramps or heat exhaustion.
• 105 A?F (41 A?C) to 129 A?F (54 A?C) may cause heat cramps or heat exhaustion, and heatstroke is possible.
• 130 A?F (54 A?C) or higher may cause heatstroke.

Prevention measures during days of high heat index will help reduce the risk of a heat-related illness. When the outdoor humidity is greater than 75%, losing body heat by sweating is not as effective, so other measures to keep cool are needed.