But that's exactly what I was saying, LOL. No need to update the DST part that often. The time itself, after it has been correctly DST adjusted (once every -insert longer interval here-), can run without interrogating anything - after all, seconds have the same duration everywhere. Basically, what I would envision is just have the DST updated at longer intervals, then use the difference compared to your local time to display the time normally (aka using your local clock), until the next DST check.
On that we agree. But Google must be using some feed as well to display that in your browser ... even if it's his own feed I'm just saying that if they can use some feed to get that info, why not everybody, and why not in Rainmeter as well? Accuracy and availabilty is all that you'd need. There are quite a few apps that display such things, which leads me to believe that they most likely used such a feed and the process isn't that complicated.
Now on doing that yourself, that's a totally different proposition, and I completely agree with you that such an endeavour is not worth the effort.