Have you set the time zone correctly in your operating system. It is not enough to just set the time and date. Right click the date/time on the windows task bar and select "Adjust date/Time" make sure the time zone is set corre4ctly and that automatically adjust for daylight saving is enabled. Have you set the locale in options > calendar >General. It Thunderbird. If the calendar is a network calendar from say Google have you set you timezone correctly on the relevant web site. All times are stared in UTC time, it is basically GMT (Greenwich Mean Time) but covered by the relevant ISO and standards grouping. This means that the time offsets applied have to be correct for a correct local time to be applied. For instance Sydney it UTC +10 hours and Adelaide is UTC time + 9:30 hours. Another thing that messes up this can be the use of Proxy servers and VPN's. This can make viewing TV on the NBC web site simple from Australia, and hide your activity grom government snoops, but make it looks to the internet like you are in the USA, so you start getting things with weird date time stamps as confusion reigns supreme over where in the world you actually are. This can include the timestamps on emails. This confusion can be worsened with the use of random exit points to the VPN so you are in the USA one hour and Russia the next.