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July 3

Correlation between the zip codes’ first digits and the time zone

Is there any correlation between the first digit of the zip codes in a U.S. state and the time zone used in the same state? In particular, can 2 states use the same time zone without having their zip codes starting with the same digit, or vice versa? GeoffreyT2000 (talk) 00:14, 3 July 2019 (UTC)[reply]

Compare zip code and time zone maps:

Rmhermen (talk) 00:26, 3 July 2019 (UTC)[reply]

They go east to west, like the time zones do. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:23, 3 July 2019 (UTC)[reply]

Looks like a poor correlation to me, with perhaps the best match between the 8's and Mountain Time Zone, by area. If you look at the differences by population, Montana is almost empty, but Nevada is more populous. SinisterLefty (talk) 12:54, 3 July 2019 (UTC)[reply]

Further, it shouldn't be surprising that the correlation is poor. The high-digit ZIP code boundaries always follow state lines, but in many places time zone boundaries do not. --76.69.117.113 (talk) 02:53, 4 July 2019 (UTC)[reply]

I do geocoding. I have to explain, almost daily, that zip codes refer to postal delivery routes. That is it. Zip codes do not share boundaries with states, counties, cities, or time zones. There are many examples of zip codes that cross state lines, county lines, city lines, etc... They aren't even contiguous. Zip codes can cover multiple unconnected areas. Zip codes are not necessarily sizeable as well. Some zip codes are point designations with no physical area. Some zip codes have no defined area and exist only as a placeholder for postal operations. All in all, do not attempt to use zip codes as a replacement for some other form of physical area. 135.84.167.41 (talk) 13:44, 9 July 2019 (UTC)[reply]