It's rather amusing that whenever SkyWests on-time performance is mentioned on the forum, the bashing begins. The first question is always 'yeah, but do you have ACARS?', and the next thing is always 'yeah, but SkyWest doesn't operate in crappy wx'.
As far as ACARS goes, yes some of the fleet has it. I'm not sure about the percentage of E120s that have it. Quite a few I think. I know that I rarely fly CRJs with ACARS installed. More of the UAX ships have it than DLC ships. With the budget cutbacks, the ACARS installation program has basically been put on hold. On the DL side, I fly ACARS maybe a few times a month. But does that mean that crews are fudging the times? I seriously doubt it. I try to be as accurate as possible with the times. The finger here can be pointed at some of the stations. DFW(an ASA station) for instance, very rarely shows us out late. I've put us out late on the manifest many many times, but the station is too lazy to assign a delay code or assume responsibility, so guess what? We're out on time. I would assume the agents do the same for ASA and CHQ flights as well. The are other SkyWest stations that probably do the same thing. But if the times are wrong, I'm one of those weird guys that will make an effort to correct them.
As far as weather goes, yes the carriers in the NE corridor are at a disadvantage. But that doesn't mean that SkyWest operates in severe VFR conditions 100% of the time. SFO has one ILS in bad wx, creates nasty delays and lots of holding. LAX does a pretty good job, but they still have some flow delays. SLC gets blizzards in the winter, lots of deicing going on. In the summer, SLC gets 90+ temps (weight restrictions) and TRWs that mess up the traffic flow. DEN gets the same basic wx as SLC, but has more runways to handle it. SW ops from DFW have to deal with the same nasty TRWs as everyone else, with lengthy reroutes and ground delays. So basically this all means that SkyWest doesn't operate in a perfect world.
How does their on-time record look so good then? I haven't the foggiest idea, since I just go to work and do my job. I've got other stuff to worry about.