[tz] [PROPOSED PATCH] Improve guesses for post-2037 Iran
Paul Eggert
eggert at cs.ucla.edu
Sat Nov 14 06:07:01 UTC 2015
* NEWS: Document this.
* asia (Iran): Predict 2038 and later DST to be March 21 thru Sept. 21.
This is not correct, but it's better than predicting no DST.
---
NEWS | 6 ++++++
asia | 11 +++++++++--
2 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/NEWS b/NEWS
index b4e1483..121e0e4 100644
--- a/NEWS
+++ b/NEWS
@@ -11,6 +11,12 @@ Unreleased, experimental changes
America/Metlakatla switched from PST all year to AKST/AKDT on
2015-11-01 at 02:00. (Thanks to Steffen Thorsen.)
+ Changes affecting future time stamps
+
+ Asia/Tehran now has DST predictions for the year 2038 and later,
+ to be March 21 00:00 to September 21 00:00. This is likely better
+ than predicting no DST, albeit off by a day every now and then.
+
Changes affecting documentation
tz-link.htm mentions the BDE library (thanks to Andrew Paprocki).
diff --git a/asia b/asia
index 5467024..f170244 100644
--- a/asia
+++ b/asia
@@ -1084,8 +1084,15 @@ Rule Iran 2032 2033 - Mar 21 0:00 1:00 D
Rule Iran 2032 2033 - Sep 21 0:00 0 S
Rule Iran 2034 2035 - Mar 22 0:00 1:00 D
Rule Iran 2034 2035 - Sep 22 0:00 0 S
-Rule Iran 2036 2037 - Mar 21 0:00 1:00 D
-Rule Iran 2036 2037 - Sep 21 0:00 0 S
+#
+# The following rules are approximations starting in the year 2038.
+# These are the best post-2037 approximations available, given the
+# restrictions of a single rule using a Gregorian-based data format.
+# At some point this table will need to be extended, though quite
+# possibly Iran will change the rules first.
+Rule Iran 2036 max - Mar 21 0:00 1:00 D
+Rule Iran 2036 max - Sep 21 0:00 0 S
+
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone Asia/Tehran 3:25:44 - LMT 1916
3:25:44 - TMT 1946 # Tehran Mean Time
--
2.5.0
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