Difference Between Two datetimes

[W. eWatson]

Roy Smith wrote:
> In article <hh9k6g$pkq$3 at news.eternal-september.org>,
>  "W. eWatson" <wolftracks at invalid.com> wrote:
> 
>> BTW, all times are local to my city. Same time zone.
> 
> Yes, but how much time has elapsed between "2009/0/04 13:01:15" and 
> "2009/06/04 13:01:15"?  Even if I tell you that both timestamps were done 
> in the same city, you don't have enough information.
> 
> Hint #1: The answer in Sydney, Bangalore, and New York are all different.
> 
> Hint #2: Two of those cities are in temperate zones, and one is in the 
> tropics.
> 
> Hint #3: If you don't pay attention to this, you will be bitten twice a 
> year.
Sort of the opposite of a stopped clock. It's right twice a day. How 
does one solve the DST problem?