Green Flag (WBGTI of 80 to 84.9 degrees F):
Heavy exercises, for unacclimatized personnel, will be conducted with caution and under constant supervision.
Yellow Flag (WBGTI of 85 to 87.9 degrees F):
Strenuous exercises or physical labor will be curtailed for unacclimatized, newly assigned Marines and Civilian Marines in their first 3 weeks. Avoid outdoor classes or work in the sun.
Red Flag (WBGTI of 88 to 89.9 degrees F):
All PT or very strenuous work will be curtailed for those not thoroughly acclimatized by at least 3 weeks. Personnel not thoroughly acclimatized may carry on limited activity not to exceed 6 hours per day.
Black Flag (WBGTI of 90 and above degrees F):
All nonessential physical activity will be halted.
Below is a link to an Excel spreadsheet automatically generated by the Automatic Heat Stress Sensor (AHSS) system. The WBGT
(Wet Bulb Globe Temperature) column is the data to reference to the flag chart above to determine current Flag Conditions.
Current Heat Flag Condition