About this site
This site was created in order to provide air density calculations using weather information provided from the National Weather Service. In this way, the information is supported by the standards and accuracy of the NWS and it's affiliates. This site was created to support auto racers who need an accurate air density reading in order to find the best air-to-fuel ratio for their engine. However this site is applicable to anyone else who could benefit from having the air density.
Currently only locations in the United States are supported but plans are underway to support international locations as well.
FAQ
I'm a drag racer. How do I use this site?
This site is designed to enable drag racers to track various weather data for the purposes of tuning their engine. It is important to track the amount of oxygen in the air in order to get the best combination of oxygen and fuel for combustion within an engine. Many factors can influence the amount of oxygen in the air including humidity, barometric pressure, and track elevation. This site helps to track that information.
What math are you using? What industry standards are you using?
I am using the motorsports standard of 60 deg f, 29.92 Hg (at sea level), and dry air (0% relative humidty). Please note that at this time I am not supporting the aerospace or automotive standards of ambient weather conditions.
What do you mean by corrected and uncorrected barometer?
The barometer reading you see when you check the weather report is a corrected value. It is adjusted to provide a standard measurement across different elevations. The calculations in this site require the uncorrected value in order to provide accurate results.
If you are getting your barometer value from the local weather report, chances are it is the corrected value and needs to be adjusted. On this website, that means that you will need to provide the elevation of the location you will be at.
If you are getting your barometer value from a barometer measuring device, it is most likely the uncorrected value and needs no adjustment. If this is the case, do not enter the elevation of your location when using the calculators on this site.
How accurate is the weather data for each track?
The weather data comes directly from the National Weather Service and, as such, is very accurate. However, the closest weather station to each track can vary in distance from a mile or two up to 20-30 miles. In addition the weather data is updated hourly. Please note, however, that the track elevation, latitude, and longitude are always taken from the track's location and not from the weather station's location. If you need to calculate density altitude with custom weather variables, there is a free calculator you can use instead.
What's up with the barometer on the forecasted weather section? Why doesn't it change?
There is currently not a readily available way to forecast barometer. As a result, the barometer value used is the current barometer value along with forecasted temperature and humidity. Plans are under way to create a general estimation of forecasted barometer.
I do not see my track in the list. Will you be adding it any time soon?
I hope to build an extensive list of tracks in the near future. Please send me your track name and location and I will work to add it to the list as soon as possible.
Credits
Information and math related to air density and engine calibration came from information provided by RaceCarBook.com
Weather and geographical info used on this site is provided by: