intel,
There are a couple of cities that are only served by specific bases, but mostly you'll see about the whole system within a year or two from about any base. The strange exceptions are SNA, which has a bizarre noise abatement departure, which is flown only by OAK crews (though everybody is qualified for it), and IAH & CRP, which are pretty much only seen by DAL & HOU crews, mainly because of the -200 currency issue. Texas based crews see a lot MORE of MAF, LBB, AMA, etc, and OAK crews may get more familiar with LAX, BUR, ONT, & SJC, SMF, SEA etc than BWI or MDW or MCO crews do, but most guys will see about all the cities before too long.
From month to month, there ARE some cities that some bases tend to see more than others, and some less than others. Not necessarily based on hard rules, just "the way things happen." For instance, I've seen a lot of MHT and very little ORF at my current base, though at another base & another time, ORF was fairly common, and MHT less so. With some digging into the bid packets, you can start to see trends about which bases have the lion's share of overnights at each city, but that can & does change over time.
Sometimes you'll hear guys comparing notes about "flavor of the month," how neither one had seen some city for about 6 months, and now both guys have a couple RONs there next month. Just the way the schedule planning shakes out.
Some cities get so much traffic that about everybody gets to see them fairly frequently, and with the traffic thru MCI, MDW, and STL, I don't know that I'd say that anybody can predictably avoid Midwest summer thunderstorms, regardless of base. Unless you bid to always stay out west, which may be an option with higher seniority.
Every city has an equal number of AM and PM crews RON... AM crew originates the jet & flies it, another crew drops off the jet to the PM crew starting their day then heads to the hotel, and another PM crew terminates the jet that one of the AM crews will originate the next day. Rarely (usually Saturday with its curtailed schedule) you can terminate a jet at the end of your day & then originate a jet the next day, but not usually. If there are any patterns like "AM crews in OMA are mostly from BWI, but PM crews there are mostly from MCO" I've never noticed it. On most hotel sign-in sheets, you generally see several bases represented.
That all make sense?