[tz] Unnecessary faux transition in Atlantic/Canary 1980 Sep/28

[Hank Wisniewski]

Howard Hinnant <howard.hinnant <at> gmail.com> writes:

> My observation is that this is a lot of transitions for one night.  Would
it not be better to delay the
> transition from "0:00 1:00 WEST” to "0:00 EU   WE%sT” by one hour, and
thus have only one transition
> instead of two?  Here is a change that does so:
> 
> diff --git a/europe b/europe
> index c64c41b..630c234 100644
> --- a/europe
> +++ b/europe
>  <at>  <at>  -2922,7 +2922,7  <at>  <at>  Zone      Africa/Ceuta   
-0:21:16 -      LMT     1901
>  Zone   Atlantic/Canary -1:01:36 -      LMT     1922 Mar # Las Palmas de
Gran C.
>                         -1:00   -       CANT    1946 Sep 30  1:00 # Canaries T
>                          0:00   -       WET     1980 Apr  6  0:00s
> -                        0:00   1:00    WEST    1980 Sep 28  0:00s
> +                        0:00   1:00    WEST    1980 Sep 28  1:00s
>                          0:00   EU      WE%sT
>  # IATA SSIM (1996-09) says the Canaries switch at 2:00u, not 1:00u.
>  # Ignore this for now, as the Canaries are part of the EU.
> 
> Howard
> 
> 

Two lines were required for 1980 because Summer Time began one hour before
the EU rules.  The second 1980 line, switching to EU rules, could have been
specified to be effective at any time from 1980 Apr 6 01:00u to 1980 Sep 28
01:00u; any time in that range, including 1980 Sep 28 00:00s, would indicate
that Summer Time ends at 1980 Sep 28 01:00u, as specified in the EU rules. 
Why one hour before the end of Summer Time was originally chosen certainly
is puzzling.  Your suggestion to change the effective time to the time of
the change, while not changing anything, does seem more logical.  However, I
would suggest, even though WEST @ 01:00s and 01:00u are the same time, that
it would be easier on the eyes and the heart if 01:00u, the convention in
the EU rules, were used.