Time Zone Configuration

I understand that time zones were created back in the 19th century and how they were related to the development of intercontinental railroads. And I get the basic concept behind them. What I can’t figure out is why they’re configured the way they are. For instance, Indiana is in the Eastern time zone except for two little nubs, one in southern Indiana and one in northwestern Indiana. Even more puzzling, northern Idaho is in the Pacific time zone, and southern Idaho is in the Mountain time zone. In a system that basically works east-west, why the aberrations that are north-south?

Political boundaries and regional practices trump actual longitude. For some US states, the decision was carried down to a more local level than the entire state. In most cases, probably because there were different counties equally adamant about which time zone was appropriate, and not agreeing.

Politics, mostly. States that have granted counties or municipalities various home-rule powers have sometimes found that they want to be out-of-sync with the rest for various reasons. It gets even more baffling if you factor in daylight savings.

As for Indiana, I believe cities like Gary and Evansville wanted to be aligned with Illinois in order to receive radio and TV broadcasts out of Chicago at the right time. Most of the rest of Indiana is centered around Indianapolis.

<nitpick>transcontinental, not intercontinental</nitpick>

Part of the Florida panhandle is the Central zone, where the other parts of the state, in the Eastern?

Parts of Indiana did not switch to daylight ST from Eastern standard, vice versa. I discovered this when travelling to Indianapolis, even though the Atlas said it was in the Eastern time zone.

It may have something to do, in the most areas, of how the Sun sets, what angle, etc., as to correlate daylight.

I know in Point Barrow Alaska, the Sun does not set from aroung mid may to aug (?).

Alaska, I know from past study used to be in 4 time zones, now it is 3.

Time in Indiana:


They TRIED to adopt Central Time, but:

There’s a set of maps there showing the counties involved, and how the time zones worked at various points.

Even that’s changed recently. As of 2006, all of Indiana observes DST.

Thanks, I was there in 2003.

Oh, geez, I can’t believe I didn’t catch that. :smack:Thanks for pointing it out!

I’m guessing it’s more important to be in the same time zone as the nearest large city. It would be pretty stupid for Coeur d’alene, ID to be an hour different from Spokane, WA (40 minutes apart) just to stay in the same time zone as Boise, ID (7 hours apart)

For example, isn’t the reason north Idaho on a different time zone is because it is close to Spokane; whereas the rest of Idaho’s population is mainly in the valley area that stretches from Emmett /Eagle / Boise all the way across the state, and is not far from Salt Lake City. It’s a long drive through the mountains to Moscow etc.

I suppose the biggest issue is to leave an area in the time zone of the nearby big city whenever practically possible. Time zones follow natural geographical barriers of low population when they can. Nothing yells confusion like the local time being different from the big city down the road. Then, it’s less confusing if awhole state is in the same time zone.

I assume northwest Indiana wants to be on the same time as Chicago. Not sure what the south’s excuse is.

You have to look at the things from the locals’ perspectives.

Take Malheur County, Oregon. Most of it is MT since the main population areas are in the Snake Rivier Valley and the people there interact with the Idaho folks in the valley more than with the rest of the state. (Lots of desert and rough terrain to the west.) OTOH, the a small sliver of the southern end of the county is PT since those folks (and there’s very few of them) interact with their Nevada neighbors.

(In this part of the US, the population density is so tiny around most of the time zone lines that so few people are affected by having neighbors in another time zone.)

As to the N-S divide in Idaho, the two parts of the state are quite geographically separated due to mountains. It isn’t easy to travel/ship/etc. between the two halves. The state should be MT based on longitude, but the northern panhandle interacts with Eastern Washington (Spokane and such) a lot, so PT fits them better. Note that the really big mountains separate them from Montana to the east, so there’s not nearly as much interaction that way. (Oh, I see people mentioning this now. Oh well.)

So, look at proximity, mountain ranges, rivers, roads, RRs, etc. and see who likes to hang out with who.

Just don’t bring up Arizona.

We have quite enough daylight, thank you very much.

In addition to the points mentioned in the OP, I’d like to protest that the time zones aren’t divided fairly. Central Zone is just way too big compared to the others.

Also, Texas should have two time zones. It’s too big for just one.

In southwest Indiana, Evansville was traditionally the hub for the area. Of course, a lot of its business came from western Kentucky and southern Illinois, which were in the Central Time Zone. South central Indiana isn’t very populous, and southeast Indiana is far more connected to Louisville and Cincinatti, both in the Eastern Time Zone.

Far western Texas (El Paso) is in the Mountain Time Zone.

What? That little measly piece? That’s puny afterthought? Why even bother?

Another reason is the unofficial use of Daylight Saving Time. For instance, both Detroit and Indianapolis were originally in the Central Time Zone. Not only did those cities want to be tied to New York City for business, by having themselves put into the Eastern Time Zone, they moved themselves one hour ahead of where they should be.

In effect they put into place, year round DST. This is one reason why Indiana didn’t want DST, because that was moving them effectively two hour ahead of where they should be.

In practice time zone boundaries have been moving west since their creation for political reasons.

Aha! It does make sense now. Thanks, everyone.

I am intrigued by the questions about Texas and about the wide swath of the country in the Central time zone, as opposed to the relatively narrow strip on Mountain time. I would have expected that each time zone would be approximately equal in geographical miles because of the daylight situation. Of course, since the advent of Daylight Savings Time, we’re not as concerned with what time daylight is. I really wish we’d just pick either Daylight or Standard time and stick with it; I hate those first few days after changing clocks when my body is still on the “old” time. But I guess that’s another topic for another day and probably the IMHO board.

So why AREN’T time zones roughly equal in miles east-west? (I do understand that with the curvature of the earth, time zones are narrower the closer you get to the poles.)

For a given latitude, they should be, ideally. A better statement might be that ideally they are 15 degrees of longitude wide. As we have been illustrating, they aren’t, except over largely uninhabited areas, because of political boundaries. For instance, many of the countries of western continental Europe all want to be on the same time. Spain is mostly west of the Greenwich meridian, and France is mostly west of the 7.5 E longitude line which should be the undistorted western boundary of the time zone they are in. But they want to be synchronized with Italy, Germany and so on.

That’s okay – mostly, we just assumed you were referring to the express train from Liverpool to Boston.

Anyway, if you think what you’ve read so far is bad, try looking at a time zone map of Africa.