Alexander Belopolsky wrote:
It looks like the decree № 59 was not implemented and replaced by decree № 147 <http://istmat.info/node/35854> which postponed the implementation until July 1, 1919. This is close to the date in tzdata, but it would still make more sense to have transition on a round UTC hour rather than at 21:28:41.
Thanks, that's interesting. Decree No. 59 says this: Первого апреля 1919 года в среднюю Гринвичскую полночь часы в каждом из поясов России поставить так, чтобы они показывали целое число часов, равное номеру пояса. Время в течение суток считать от 0 до 24 часов, принимая за начало суток полночь. which Google Translate renders as: On April, 1919, in Greenwich Mean midnight hours in each of the Russian zone to put so that they showed a whole number of hours equal to the zone number. Time during the day to count from 0 to 24 hours, taking the start of the day at midnight. I interpret this to mean that all Russian zones were supposed to switch to the new system at 00:00 GMT on the specified date (April 1 in that decree, but delayed to July 1 in Decree No. 147). Of course this would affect only the territories actually controlled by the Bolsheviks at the time. (Also, of course the actual switches were not implemented precisely; there was a war going on, after all.) Proposed patch attached, and installed into the experimental repository on Github.