BALTIMORE, MD (August 10, 2021) With temperatures expected to rise in the Baltimore region and the heat index forecasted to reach over 100 degrees Fahrenheit over the next few days, Baltimore City Health Commissioner Dr. Letitia Dzirasa has issued a Code Red Extreme Heat Alert for Tuesday, August 10 through Friday, August 13. The heat index is a measure of air temperature and relative humidity and indicates how hot it feels to the human body.