Question about time period transition points

[Mike Giroux]

On Mon, Feb 14, 2011 at 2:44 PM, Paul Koning <paul_koning at dell.com> wrote:
>
> On Feb 14, 2011, at 2:39 PM, Adam Vartanian wrote:
>
>>> Phrased differently, for the Americas/NewYork transitions this spring:
>>> 1) Is the time coordinate value at the instant of transition "2:00 AM" or "3:00
>>> AM" (NIST says "begins at 2:00 a.m. on the second Sunday of March")
>>>
>>> 2) Is the designation of that coordinate (in the local New York City timezone)
>>> "EDT" or "EST"?
>>
>> At least in the United States, time transitions from 1:59:59 AM EST to
>> 3:00:00 AM EDT.  I don't know if other countries have different rules,
>> but it would be surprising to me if they did.
>
> The changeover time is just as much an arbitrary political decision as all the other aspects of DST change.  So yes,
> you can find a variety of changeover times.  You can find them in the "AT" column in the rules files.

Paul,

That makes sense.  However, combining your answer and Adam's, it looks like the
"AT" time isn't actually reached?

The current "northamerica" file shows an AT time of 2:00, not 1:59:59.

Am I misreading it?

Thanks,

Mike