At some point I had to face it! what’s the difference between UTC and GMT?
From what I see in rails, GMT takes into consideration DST, Daylight Savings Time, whereas UTC is always the same.
I am in CET, Central European Time. As I am writting we are in may, so we are in UTC +2, but we are GMT +1. In wintertime we will go back to UTC +1 but still we will be in GMT +1.
About DateTime standards.
We have all experienced at some point the pain of translating US datetime, which are yyy-dd-mm to the (I have to say) more reasonable standard yyy-mm-dd. Why is the latter more logical to me? because it can be sorted in an easier manner.