Live Flight Tracking

Is there a standard amount of delay between when a flight passes over my town versus when the flight tracking map shows it crossing? I am continually going outside expecting to see an aircraft going overhead when the map shows it on a course that will have it doing so without success. I have experimented with lead time - seeing the flight on the map 5 to 10 minutes out (assuming the speed shown on the map) but still miss seeing them in person. I do have a pretty good view of the sky to the south and can watch airliners for around 10 minutes on east west routes. I'm assuming that is between 50 and 60 miles.
But I've had little success being able to match up what I'm seeing with what the flight tracker shows.

I live about 6 miles west of KVEL airport in Vernal Utah. I do see a lot of aircraft when I'm out and about but am not close to the computer. According to the Live Flight Tracker, we have a lot of flights from KLAX to Europe coming close to our town every day as well as a lot of domestic flights out of KSLC, KSFO, KDEN that also pass very close to our town.

I'd like to know if there is a timing trick to matching the tracker to my real time viewing. And would love hearing about how other users of the site have fared in their endeavors to do the same. Thanks.

Go to About FLightAware (on the left side of every page in this site) to read the FAQs. The delay is explained there in the first question.

Thanks very much rw812. Found it. From 30 seconds to 5 minutes. The variation of delay would explain some of my frustration. But having a better idea will surely help.