Density Altitude is the actual weather conditions for the specific time in feet.
For instance. Atco is 50 feet above sea level. If you run at Atco in the summer, with a temp of 90 degrees with 50 percent humidity and a barometric pressure of 29.50 you come up with a DA of 2816 feet above sea level actual air conditions. Not very good for running good times.
Then, you run in December at Atco, with a temp of 35 degrees with 50 percent humidity and a barometric pressure of 30.40 and the DA is -2071. That is awesome for running good times. Air so much cooler and denser.
So take both these situations above, and take the same car without changing any mods. In the summer, the car runs a 13.40 lets say. That same car in the December weather conditions I stated above runs a 12.73 without changing a thing.
Thats why paying attention to the exact conditions at the time of a run is so important. If run a time in the winter, then change gears and don't run again til summer, your times won't be as good. You would think the gear swap sucked and did nothing for you, when in reality it did.
Still, your timeslip is your timeslip. Jay ran those times, and with the DA for that day, is right on with what he should have run. Nice runs Jay.
Starkie