This calculator uses the Motorsports Standard Atmosphere (MSA) at sea level. (Not ISA - International Standard Atmosphere)
Use this calculator to find your anticipated ET for Today's conditions.
Input a run for the 1st Run, using that runs weather conditions.
Then input Today's weather conditions.
After clicking the Submit button, you will be given an ET/MPH for what your car will run Today.
(If nothing has been changed on the car since that run)