GeoNames Forum

First let me say, This is great data and very useful to us. I have everything I need except for one thing and I may be looking in the wrong spot for this information. I need the Start Date and End Date for Daylight Saving Time for each TimeZone in the TimeZone table.
Is this listed somewhere where I can pull it into my database?

Thanks Again for this great information.

The DST rules are not just dates but complex rules that change all the time and give all dates of the past and also the dates of the future as they are currently defined and known. GeoNames is referring with the timezoneId to the olson database that models these rules.
The only thing we could do is to add the next date of change to the daily export file. I don't know how useful this would be, as it would not say anything about the past and about the dates after the two next dates of time change.

Best

Marc

I haven't had much luck trying to download the tz data using the ftp they provide. I must be doing something wrong.

So are you saying that because GeoNames uses the TimeZoneID from the Olson Database that there is not Start Date and End Date for Daylight Saving Time?

Here is my dilemma, because I am on an "Intra"network that is separated from the WWW, I cannot access the any data through web services. I have to do updates using your flat files.
So I created a database and imported the data, but I can't code in whether or not to apply daylight savings time (whether or not to use dstOffset) because I don't have a Start Time and End Time for Daylight Saving Time for each TimeZone.
I've tried using[url]http://www.timeanddate.com/time/dst/2011.html
[/url] to cross reference the timezones to the cities but not all cities are on it.

I wouldn't care if each year I had to update my TimeZone DB with new Start and End Dates for DST because I know they change every year.

How does the Olson DB know when to start or stop DST?

you don't need to download the tz data. It is very complex, but included in many operating systems and programming languages. Java for instance has the rules included. Check what is available for your environment, you don't have to reinvent the wheel.

Best

Marc