[tz] Historical data for Iran

Roozbeh Pournader roozbeh at unicode.org
Mon May 30 11:40:46 UTC 2022


The timezone database currently lists Iran  switching to standard time in
1946. I've been doing some research on the history of the adoption of
standard time by Iran, and while it's very hard to find much, I found that
the correct date is actually 1935.

Here's an order from the Cabinet to the rest of the government to switch to
Tehran time, which is mentioned to be already at +03:30:


Just in case that goes away, I also saved a copy at archive.org:


Here's my translation:

"Circular on Matching the Hours of Governmental and Official Circles in

Approved 1314/03/22 [=1935-06-13]

According to the ruling of the Honorable  Cabinet, it is ordered that from
now on in all internal provinces of the country, governmental and official
circles set their time to match Tehran time (three hours and half before
Greenwich). It is required to mind the above order.

For Minister of Judiciary, Dr Matin-Daftari"

Now, I still haven't found out when Tehran itself switched to +03:30 (let's
assume some time earlier in 1935), but it is clear that standard time in
Iran started on 1935-06-13 and not 1946.

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