I am using timezone API to get the dstoffset and gmtoffset. But i want to know that whether the timezoneId key which is available changes according to DST or not. For Example: "http://api.geonames.org/timezone?lat=47.01&lng=10.2&username=demo" this shows current timezoneId as "Europe/Vienna" for Austria country. As of now DST is applicable in Austria so this is the timeZoneId but once the DST is over does the timeZoneId gets Changed or remain the same thorughout the yes.
Hoping for postive and quick reply as soon as possible.
The timezomeId is referring to the iana timezone project ('Olson Timezone'). The DST rules per timezoneId are maintained in the iana tz project, which is included in most programming envs (like java).
Best is to google for the timezone support in your environment, if it is not natively supported there are for sure 3rd party libs for this.
All you then need is the timezoneId of a location and the lib will tell you where it is DST for particular date.