Vegas flight delays

Hi,
Am travelling on VS43 to LAS soon and have been keeping an eye on it's actual arrival time into LAS over the last few weeks. It seems to have been at least an hour later most days - does anyone know if there's any reason for this and if it is likely to improve?
I don't want to plan too much on the first day especially if I'm going to be a couple of hours late!
Cheers.

[honey lamb]

If it has been over the previous couple of weeks would that have had anything to do with the fact that the clocks went forward in the US two weeks before we did?