www.dragtimes.com then click tools and scroll to DA Calculator - Density Altitude Calculator. Choose your track and date and then find your closest time of day. Click that and it gives you a close estimate.

If you were racing this past saturday at 11pm ish, there was some crazy humidity. This is your conditions.

Track Elevation:410 feet above sea level
Air Temperature:37.4 degrees F
Barometric Pressure:29.31 inches Hg
Relative Humidty:93%


Density Altitude: -146 feet
Relative Density: 100.43 %

I'm jealous once again by that sick DA. OH so lucky.