My software records time events on the computer and it does it using whatever timezone and daylight saving time settings are on this computer. I realized too late that, while storing timestamps, I am not accounting for this daylight adjustment process. So, if hypothetically speaking, the daylight adjustment happens today at 9:00 am and I am writing my timestamps every second I will have something like that: … 8.58 8.59 9.00 10.01 (without timesaving should be 9.01) 10.02 (without timesaving should be 9.02) … When I am reading my timestamps back I am constructing timezone and using it for timestamps manipulation std::string gmt = (boost::format("TMZ%1% TMS1:00:00,M3.2.0/02:00:00,M11.1.0/02:00:00") % gmtoffset).str(); , but this one-hour gap persists, as I now think it should. The question is: is it possible to do manipulation with datetime library to remove this gap without hard-coding one hour removal after specific date/time of daylight saving time?