View Full Version : Time zone confusion

05-09-2016, 01:18 AM
Confused because time zone are inherently confusing.

I am in Phoenix, one of the few parts of the US that is smart enough to not do daylight savings time. I am trying to set up a calendar entry that repeats weekly. The times for the entry are defined as Washington DC time. I want to enter the event times as they are defined and have the time I (in Arizona on MST) see change as DC goes on and off DST.

As I see the situation, there are three times defined for DC:
Eastern Standard (GMT - 5, all year),
Eastern Daylight Time (GMT - 4, all year),
DC time, which switches between EST and EDT.

DJO provides me with Eastern Time and Eastern Daylight Time, with no definitions given.

1. How do these two times map to the three times I listed above?

2. Which one do I use to get the proper time shown here in Arizona all year round?


05-09-2016, 08:22 AM
Pls2000 this is a good question.

The time zone value list is read from your phone. So it changes with phone maker and carrier.

DejaOffice automatically accounts for the Daylight time.

So you should create your Weekly appointment and you can choose any value for "Eastern Time" or "Eastern Daylight Time". Let's say you make it at 10am Eastern Time. You will see that it is displayed at 7am your time through early November. Then after November 6, you will see it shows at 8am on your phone. Try this out. It works great.

05-11-2016, 03:12 AM
Except that's not the way it works..

My calendar entry is for 11 pm Washington DC time. Since AZ does not do DST, right now the difference between Phoenix and DC is 3 hours.

If I set the calendar entry to Eastern Daylight Time, the entry shows at 8 pm, with is correct. I do not know what this will do in November when DST ends.

If I set it to Eastern Time, the entry shows at 9 pm, which is wrong now. Again, I don't know what this will do in November.

If I turn off date time from network on my phone and manually change the date to December, without changing the phone's time zone, then
Eastern Daylight Time still gives me 8 pm, and
Eastern Time still gives me 9 pm.

So it looks like it is not changing as DST ends. I don't know if this is a valid test, though.

I do know that Mountain Time gives me proper local time without switching to DST, but I suspect there is some intervention by my cell carrier involved.

05-11-2016, 08:46 AM
pls2000 - You should not be setting the date/time on your phone to check.

To check the appointment, just go to the month view, roll forward to November, and then click on a day to see the day view.

Your time zone is commonly called "Arizona Time" which is Mountain Time without DST, sometimes noted as Mountain Standard Time.

For your appointment you want to use Eastern Daylight Time by which the developer means - use Eastern time with Daylight adjustment. There is no location in the US any more that uses Eastern Standard time, although some areas of Indiana did this until about a decade ago.

I'll have the App adjusted to add the technical details on the settings. That way it will clarify what is meant so people can set it more accurately.

05-12-2016, 01:47 AM
Woo hoo! It works.