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In article <392@shodha.dec.com>
devine@shodha.dec.com (Bob Devine) writes:

	Here is the official list of standard timezones.  There are two
	ways of naming the timezone -- zone numbers and zone letters.
	Negative zone numbers are east of 0 degrees latitude (the Prime
	Meridian); positive numbers are west (note: this is opposite the
	Unix convention).

The sign convention, in fact, goes the other way.  Negative numbers are
used west of Greenwich (i.e., earlier than UTC -- *subtract* the amount
from UTC to get the local time), while positive numbers are used east of
Greenwich (i.e., later than UTC -- *add* the amount to UTC to get the
local time).

If you used ARPA RFC822 as your source, you should be aware that RFC822
got the signs wrong in its definition of the one-letter zone names.  For
example, zone "U" (Pacific Standard Time) is -8, not +8 -- RFC822 to the
contrary notwithstanding.  This error is well known among the initiated
:-} and has been noted in some subsequent RFC discussing Internet host
requirements, but RFC822 itself was not corrected.

	In addition to the above 24 zones, there are some country-
	specific `timezones'.  The Newfoundland province is at +3 1/2;

Actually -3:30, not +3:30; see above.

In Canada, BTW, TV programs are generally broadcast at the same time in
each time zone *except* Newfoundland; residents of "The Rock" watch TV
shows at the same time as people in the Atlantic provinces (New Bruns-
wick, Nova Scotia, and Prince Edward Island), at a local time half an
hour later than in other provinces.  This custom has given rise in Can-
ada to such jokes as "the world will end tonight at midnight (12:30 New-
foundland)".

	Venezuela is at +5 1/2;

According to the 1984 World Radio/TV Handbook, Venezuela uses UTC-4.
You may have been thinking of Surinam (formerly Dutch Guiana), which
uses UTC-3:30 as its time zone.

No part of South America is far enough to the west to justify using
UTC-5:50 as its time zone.  The only country that might reasonably con-
sider this time zone is Costa Rica -- and they use UTC-6.

	India uses -5 1/2; and Iran uses -3 1/2.

Again, as indicated above, reverse the signs:  +5:30 and +3:30.

	For the really different, consider that Saudi Arabia follows its
	own rule for setting clocks by using the time at sundown as mid-
	night;

Saudi Arabia used to do this, but stopped the practice some time ago and
now uses the UTC+3 zone.

	Afghanistan may still (unless the Soviet invasion forced a
	change) use a time that is -4 hours 26 minutes from UTC.

Afghanistan has used UTC+4:30 for some time.  This change may indeed
have arisen from the Soviet invasion; I don't have enough information at
hand to verify whether this is so or not.

	On the coincidental matching of zone names (such as for the USA
	and Canada), the zones are still different due to the handling
	of daylight saving time rules.

Canada has, for convenience' sake, followed along with whatever the USA
has done with respect to daylight savings time for some time now.

Back to Newfoundland for a minute.  Newfoundland briefly experimented
with "double daylight savings time" -- moving clocks *two* hours ahead
in the summer.  I don't think they are doing this any more, though.

-- Rich Wales // UCLA Computer Science Department // +1 (213) 825-5683
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