Between 1966 and 2007, various other tweakings have taken place based on economic considerations (oil issues in the 1970's) or other considerations (2005 Energy Act) to get us to where we're at today. However, throughout the Northern Hemisphere daylight time is inconsistent in its implementation -- with Canada generally in alignment around the United States' daylight time practice, while the rest of the hemisphere is dealing with varied implementation of daylight time.
- The vast majority of Europe utilizes daylight time from the last Sunday in March through the last Sunday in October (known as "summer time" over there). There are a few exceptions but the vast, vast majority of Europe is consistent on standard/daylight time.
- Russia is permanently on daylight time (an hour ahead of standard), having ended the seasonal adaptation of daylight time in 2011 and permanently shifting their clocks ahead one hour.
- Mexico utilizes the old US schedule -- first Sunday of April through last Sunday of October -- with the exception of ten border cities along the US-Mexico border, which follow the US schedule, and the state of Baja California (which also follows the US schedule).
- Much of Asia does not implement daylight time.
- Much of the Middle East follows closely to the Europe model but goes last Friday in March to last Friday in October, with Israel going ending daylight time on the Sunday in between Rosh Hashanah and Yom Kippur.
Granted, tropical states and countries are likely to have no need for daylight time...but for those who do implement it, the lack of consistency across the board makes for relatively unique couple of weeks each year as some parts of the world are on daylight time while some aren't but will be.
In my little world, starting daylight time as early as we do is somewhat unnecessary. I'm a morning person and prefer earlier sunrises continuing through much of March. Given how volatile many a March have been climatically, we're not always able to benefit from daylight time giving us later sunsets...although this year will be much, much different. Granted, there will always be some sort of localized variety in how daylight time is implemented. However, with the increasing connectivity of the world having a "standard" of when daylight time is utilized may end becoming a reality at some point. Perhaps it's an "all in" approach like Russia has (there have been occasional suggestions from pundits and "experts" that have advocated year-round daylight time in the US for various reasons whether safety or economic) or something compromising the European and US setups or something completely different. In any case, daylight time always brings about its share of fans and detractors, with folks across many countries scurrying to change clocks and get used to "losing" that hour they will get back months later.