AUGUSTA, GA (WFXG) - It's something that seems to happen at least once a summer: a sweltering heat wave gripped the country. But what is exactly is it? The National Weather Service officially defines a heat wave as three or more days in a row with temperatures above 90 degrees.
In Augusta, we see an average of 76 days with temperatures at or above 90 degrees. A heat wave here is measured by the heat index. The National Weather Service in Columbia issues heat advisories when the heat index jumps to 110. They'll issue excessive heat watches or warnings when the heat index hits 115 or higher.