attention Paul Eggert: I am reading through the comments for zone Pacific/Tonga and there you write on 2006-03-22: ... go with Mundell where "Mundell" means his article by Don Mundell http://www.tongatapu.net.to/tonga/homeland/timebegins.htm In reading this article, I cannot see where he places the transition from standard meridian 185°e (12:20h) to 195°e (13:00h) into the year 1999. What I read is that he talks about the change in New Zealand timezone from meridian 172.5°e (11:30h) to 180°e (12:00h) on 1946-jan-01, and that the Crown prince Tungi, wanted to maintain the 50 minutes difference to New Zealand. But it appears that no change was made then, in 1946, and Tonga now had only a 20 min difference to New Zealand. I cannot see how you derive a change in 1999 from what Mundell writes. Please clarify. Shanks has this change in 1968, but as usual he gives no source. PS: does anyone know of a way to get access to old IATA SSIM manuals? I rember those being voluminous books which travel agents used to look up flight schedules. For several years, I used to collect older copies of these manuals from a travel agent and use them to look up timezones, as they were documented for each airport, together with begin/end dates for DST if such a change fell into the two-month period a manual covered. I had a collection of many years from the late 1970ies and the 1980ies, but threw them out when I got hold of Shanks' books. Now I would love to check some information in them again, but so far have been unable to find where copies are held in an archive.