You would still store both future times with offset. When calculating an offset for a future time you take the future time and the zone together to determine the exact time with offset. DST is predictable.
DST schedules change several times each year, often with little prior notice. They changed in North America in 2007, which caused a lot of pain for software that thinks DST is predictable, such as Microsoft Exchange.
Macha|5 years ago
No it isn't.
* Europe postponed planned DST abolition due to COVID19: https://www.timeanddate.com/time/europe/eu-dst.html
* Argentina had a period of deciding each year what the DST dates would be until one year they just decided not to: https://en.m.wikipedia.org/wiki/Daylight_saving_time_in_Arge...
* Morocco and Yukon, Canada made updates to their DST policies earlier this year: https://mm.icann.org/pipermail/tz-announce/2020-April/000058...
fanf2|5 years ago