Is The TimeZone Information Just Wrong?

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Newguy20383746
Posts: 1
Joined: 2020/05/15 18:56:45

Is The TimeZone Information Just Wrong?

Post by Newguy20383746 » 2020/05/15 19:07:24

I feel like I must be misunderstanding; but it looks like the timezone data I get on CentOs is wrong.

zdump -v /usr/share/zoneinfo/America/Whitehorse
/usr/share/zoneinfo/America/Whitehorse Sun Nov 4 09:00:00 2018 UTC = Sun Nov 4 01:00:00 2018 PST isdst=0 gmtoff=-28800
/usr/share/zoneinfo/America/Whitehorse Sun Mar 10 09:59:59 2019 UTC = Sun Mar 10 01:59:59 2019 PST isdst=0 gmtoff=-28800
/usr/share/zoneinfo/America/Whitehorse Sun Mar 10 10:00:00 2019 UTC = Sun Mar 10 03:00:00 2019 PDT isdst=1 gmtoff=-25200
/usr/share/zoneinfo/America/Whitehorse Sun Nov 3 08:59:59 2019 UTC = Sun Nov 3 01:59:59 2019 PDT isdst=1 gmtoff=-25200
/usr/share/zoneinfo/America/Whitehorse Sun Nov 3 09:00:00 2019 UTC = Sun Nov 3 01:00:00 2019 PST isdst=0 gmtoff=-28800
/usr/share/zoneinfo/America/Whitehorse Sun Mar 8 09:59:59 2020 UTC = Sun Mar 8 01:59:59 2020 PST isdst=0 gmtoff=-28800
/usr/share/zoneinfo/America/Whitehorse Sun Mar 8 10:00:00 2020 UTC = Sun Mar 8 03:00:00 2020 MST isdst=0 gmtoff=-25200
It's going from PST to PDT to PST .... and then to MST???

When I search online, Whitehorse should be PDT
(https://www.timeanddate.com/worldclock/ ... whitehorse)

It's not just Whitehorse either, I see the same thing in America/Dawson - I haven't checked 'all' of the timezones, these are just two I stumbled onto.

I have an Ubuntu install and it does not have 'MST' listed, instead it has PDT/PST

Code: Select all

$ rpm -q tzdata
tzdata-2020a-1.el7.noarch
I've tried to update tzdata, but it seems like I'm current.

Is this a bug? Is this the appropriate place to ask about it? Really appreciate any info.

desertcat
Posts: 746
Joined: 2014/08/07 02:17:29
Location: Tucson, AZ

Re: Is The TimeZone Information Just Wrong?

Post by desertcat » 2020/05/24 08:08:38

Newguy20383746 wrote:
2020/05/15 19:07:24
I feel like I must be misunderstanding; but it looks like the timezone data I get on CentOs is wrong.

zdump -v /usr/share/zoneinfo/America/Whitehorse
/usr/share/zoneinfo/America/Whitehorse Sun Nov 4 09:00:00 2018 UTC = Sun Nov 4 01:00:00 2018 PST isdst=0 gmtoff=-28800
/usr/share/zoneinfo/America/Whitehorse Sun Mar 10 09:59:59 2019 UTC = Sun Mar 10 01:59:59 2019 PST isdst=0 gmtoff=-28800
/usr/share/zoneinfo/America/Whitehorse Sun Mar 10 10:00:00 2019 UTC = Sun Mar 10 03:00:00 2019 PDT isdst=1 gmtoff=-25200
/usr/share/zoneinfo/America/Whitehorse Sun Nov 3 08:59:59 2019 UTC = Sun Nov 3 01:59:59 2019 PDT isdst=1 gmtoff=-25200
/usr/share/zoneinfo/America/Whitehorse Sun Nov 3 09:00:00 2019 UTC = Sun Nov 3 01:00:00 2019 PST isdst=0 gmtoff=-28800
/usr/share/zoneinfo/America/Whitehorse Sun Mar 8 09:59:59 2020 UTC = Sun Mar 8 01:59:59 2020 PST isdst=0 gmtoff=-28800
/usr/share/zoneinfo/America/Whitehorse Sun Mar 8 10:00:00 2020 UTC = Sun Mar 8 03:00:00 2020 MST isdst=0 gmtoff=-25200
It's going from PST to PDT to PST .... and then to MST???

When I search online, Whitehorse should be PDT


(https://www.timeanddate.com/worldclock/ ... whitehorse)

It's not just Whitehorse either, I see the same thing in America/Dawson - I haven't checked 'all' of the timezones, these are just two I stumbled onto.

I have an Ubuntu install and it does not have 'MST' listed, instead it has PDT/PST

Code: Select all

$ rpm -q tzdata
tzdata-2020a-1.el7.noarch
I've tried to update tzdata, but it seems like I'm current.

Is this a bug? Is this the appropriate place to ask about it? Really appreciate any info.
OK I will assume that you are referring / using something like the "World Clock" app. I will also assume that you have a picture of a map of the world that when you move your mouse and hover over a place it show the local time of that place. This is a great app but it does have its limitations. For one if you are off even a hair it may show a whole different time. I am surprised it even lists MST, PDT, EST, EDT, etc. There are a few places where the time remains the same throughout the year. Arizona which is in the MST is always on MST ie. it does not change where as say Denver, CO, which is also in the Mountain Time Zone has both MST in the Fall, and MDT in the late Spring to Summer.

I will have to assume that you live in or near, or someone you love lives in or near Whitehorse Canada, located in the the Yukon Territory. Whitehorse is in the Pacific Daylight Timezone. Like AZ it is ALWAYS the same time throughout the year. Daylight Savings is an obsolete holdover from the time when America was mostly an agrarian society and clocks were relatively scarce. So you would "Leap Forward" in the Spring, and "Fall Back" in the Fall. Most "World Clock" and the like automatically self correct for Day Light Savings and usually refer to something like ntp servers in the area, which is why your Cell Phone self corrects for the time zone you are in. Say you are in New York in the Winter (EST) and fly to San Francisco (PST) on the same day. San Francisco is 3 time zones behind New York. Right now it is 02:43 in New York, but it is 23:43 in San Francisco. On the same day you fly to say Phoenix, AZ well MST is one hour ahead. Say you leave at 0800 hrs San Francisco PST time, it is 0900 hrs MST in Phoenix. However if you take the same trip in July and it is 0800 PDT it is still 0800 hrs MST in Phoenix. Your Cell Phone will show the exact local time it is in. Most "World Clocks" are part of the Global Network of clocks, indeed ntp stands for Network Time Protocol which allow clocks to sync to one another.

Now most "World Clocks" are not precise enough to list EVERY city on the face of the earth, rather just a handful, this is where it becomes important to know what timezone you are in. New York is in the Eastern Time Zone. Say go looking for the Time in Miami Fla. Sorry you will not find Miami, but since Miami is part of the Eastern Time Zone Miami will be the same time as New York. Go looking for San Francisco, and you will not find San Francisco, but you will find Los Angles, thus San Francisco will be the same time as Los Angles. Just for fun I went looking for Whitehorse, Canada and just accidentally found it, after stumbling across Dawson Creek and Fort Nelson. Fort Nelson is located in Mountain Standard Time Zone, likewise for Dawson Creek.

"Yukon has chosen to align with the Pacific Time Zone (UTC-8) since 1973. Yukon currently observes Pacific Standard Time from early November to early March every year. Yukon currently observes Pacific Daylight Time from early March to early November every year."

Then Came across this:

B.C. Premier John Horgan says British Columbia won't have permanent daylight saving time until next year. Horgan spoke with CTV News on Friday, fresh off of trips this week to the Yukon and Washington state, where he spoke with leaders about ending seasonal time changes and moving to a permanent daylight time.Oct 4, 2019

Does Yukon have Daylight Savings?
Year-Round Daylight Saving Time
On March 8, Yukon residents set the clocks forward one hour to Pacific Daylight Time (PDT). According to a March 4 announcement from the Yukon government, the Canadian territory will not turn its clocks back to Pacific Standard Time (PST) in the fall but remain on PDT indefinitely.Mar 9, 2020

Thus the answer to your question seem to be to NO it is NOT a bug it seems to be that things are in a state of flux up there. Likewise BC may be moving to permanently stay on Mountain Standard Time the same as Phoenix AZ. Thus Yukon if it elects to stay on Pacific Daylight Time (PDT) and if BC elects to stay on Mountain Standard Time would in effect have the same time zone (PDT or MST). Right *NOW* both Whitehorse in the Yukon and BC such as Dawson Creek and Fort Nelson are on the same time zone as Phoenix and Tucson, AZ.

P.S. If you have something that gives PDT, MST, EDT then it is "time" to find a new time app, as it only confuses things -- that or simply move to a 24 hour clock. I currently use World Clock since I have many many friends spreed all the way from the West Indies, to Washington States and points in between.

Hope this helps.

D'Cat

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