New site with North American Time Zone borders

Chris Walton Chris.Walton at
Sat Feb 12 06:18:22 UTC 2011

Steve J.,

As you are aware, there are no official time zone boundaries in British Columbia.
And the fact that much of the province is mountainous and uninhabited means that the time zone boundaries are somewhat arbitrary.

When I made the time zone boundary lines on my map for BC I made sure that:

a)      Communities that are known to be in a specific time zone are the correct side of the boundary lines.

b)      Boundary lines cross roads in the approximate location of documented "time zone change" road signs.

c)       Boundary lines cross only major highways and avoid crossing small roads.

d)      Boundary lines follow regional district borders or electoral district borders where possible.

e)      Otherwise, the lines follow watershed (a.k.a. drainage basin) boundaries.
Note that many of the regional borders in BC follow the watershed boundaries as they pass from one mountain peak to the next; these lines make for good time zone boundaries because they lie high up in the mountains where nobody lives.  The only roads that cross the watershed boundaries are the main highways.

Specifically for the line from Riondel to Glacier NP: I ran the line north along the border between Central Kootenay Regional District and East Kootenay Regional District.  It then runs north-west along the border between Columbia Shuswap Regional District and Central Kootenay Regional District and then follows the Conrad Icefield up to the South East corner of Glacier National Park.
Note that Glacier National Park officially operates on Pacific Time and there is supposedly a time zone sign on the trans-canada highyway 600m outside the park.

As for the highway 97 crossing,  all I have to go on is this website:
It says that the time zone changes just south of Pink Mountain.

F.Y.I. I may be somewhat unreachable next week.  If I don't respond to e-mail please be patient.

From: Steve Jones [mailto:stevejones at]
Sent: February 11, 2011 7:42 PM
To: Chris Walton; 'tz at'
Subject: RE: New site with North American Time Zone borders

At 11:45 2/11/2011, Chris Walton wrote:

Back in 2007 I posted a Canadian time zone map in one of the Google Earth forums.


Very nice!  My implementation of the kml version is much less ambitious, but I hope to keep it at least accurate.  I'm very grateful for the feedback on my errors and I will roll it into my next release.

I've also mimicked your shape for the east Kootenays for my next release.  Are you certain that the border from just north of Riondel to Glacier NP lies to the east of the lake road?  I had it running through the lake and then up the Duncan river from there.  I can't recall where I got that.

I also had the border of the no-DST area of BC near Dawson Creek drawn a bit too far north.  That line bisects Hwy 97 twice, once between Chetwynd and McLeod Lake, and again just south of Sikanni.  I wish I knew the precise coordinates of those two transitions.  Do you happen to have that?

I guess we should assume that Petit-Mécatina is now on AST year round as you have indicated.

Interesting that the Quebec/Labrador border between Blanc-Sablon and L'anse-au-Clair is apparently a 90 minute transition in the summer time when it separates Atlantic Standard from Newfoundland Daylight.  I can't recall running into any other instances of a border transition being over 60 minutes.  It must be very confusing keeping the ferry departure/arrival times straight for the St. Barbe / Blanc Sablon ferry.

Thanks again.


Steve Jones
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