Changes

While this makes the storage and calculation of correct times relatively straightforward it becomes impossible to reliably calculate the actual local time at which the data was collected when changes in time zones start to come into play.  

While this makes the storage and calculation of correct times relatively straightforward it becomes impossible to reliably calculate the actual local time at which the data was collected when changes in time zones start to come into play.  

E.g. In the simplest scenario half of your data will be off by one for data recorded during daylight saving time but displayed when being in standard time and vice versa. Things get even more tricky if you travel or move between time zones. For all of these cases the only way to reliably calculate the local time is by knowing the geographic location for each observation.

E.g. In the simplest scenario half of your data will be off by one for data recorded during daylight saving time but displayed when being in standard time and vice versa. Things get even more tricky if you travel or move between time zones. For all of these cases the only way to reliably calculate the local time is by knowing the geographic location for each observation. If

you have reliable geolocation information for yourself, then consistently storing all data in UTC might be the easiest approach, as you don't have to handle different timezones when merging data.

==== Data in local time ====

==== Data in local time ====