ZingChart has the ability to render charts to UTC format which makes addressing time issues easier and can make it easier to deal with daylight savings. To set time to UTC use
utc: true in the top level object. This will set all times to UTC rather than to the end users machine time. ZingChart also has the ability to set an offset to UTC time.
Of course what time it is and if daylight savings is in effect can get quite difficult given an end users location. As an example, United States may change to daylight savings time one day, then the UK may change to daylight savings time on a later date. ZingChart does not have a way to handle this natively.
Using UTC and timezone offsets you have the facilities to handle any case, but be prepared to address that logic yourself.