Implications of Proposed Changes to Daylight Saving Time in the United States

This past week, I’ve contacted and spoken with several legislators on the plethora of proposed changes to use of daylight saving time around the States. I even had a call from my friend, Rich Kaplan, the new CEO over at the Microsoft Alumni Network, reminiscing over a few of these recent moves. The efforts fall under two main proposals: to move their state to perpetual daylight saving time, as is the case in Florida, Mississippi (died in committee) and New Mexico*; or, to move to permanent standard time, as proposed in Alaska, Oregon, South Dakota, Texas, Utah** and Washington. (I recently heard that the bill to adopt daylight saving time in Arizona has been held up by the House leadership, effectively dead in committee.) I’m not sure what will happen in Florida and New Mexico, given that the United Sates Code (15 U.S.C. §6(IX)(260-7)) stipulates that states shall either implement the semiannual daylight saving time changes or remain on standard time throughout the year.

Asked what I worry about this now, I recalled Winston Churchill’s quote:

“Let our advance worrying become advance thinking and planning.”

I appreciate that the legislators in several states have thoughtfully called for such changes to take effect in 2017 or later (2021, in Oregon). But a few, like Texas and Washington, would have the changes as early as fall of 2015. Without adequate time to react, such changes can be challenging for individuals to manage and for companies to support. Not a very united effort in the States as a whole.

That’s why Microsoft has recommended (via the tab “Microsoft Policy in Response to DST/TZ Requests” in the left nav of the page) that governments take at least one year from the time the proposals are enacted into law for the change to occur. As an example, I look to the timeline provided in the Energy Policy Act of 2005, outlining sweeping changes to daylight saving time in the United States, that allowed for nearly a year and a half before the change was implemented.

But just as important as the time needed to implement these changes, also consider the technical implications of moving to permanent daylight saving time rather than moving solely to standard time.

imageAs noted in my last post, a few states have proposed to move to year-round standard time and drop daylight saving altogether, a fairly straight forward approach. Given that many devices (PCs, phones, tablets and services) allow you to select whether or not products use a daylight saving time offset, shifting the device between daylight saving and standard time twice a year is fairly simple, and turning off the automated change is quite simple. In Windows, you may check the option for the device to “Automatically adjust clock for Daylight Saving Time” if your time zone observes daylight saving time and you want your computer’s clock to be adjusted automatically when daylight saving time changes. (In the States, that’s on March 8, 2015.)

But moving to permanent daylight saving time may not be easily implemented on devices that are no longer supported and don’t receive updated rules: this includes computers, mobile phones, embedded devices, connected systems and services. For instance, older operating systems that are out of support (such as the venerable Windows XP) no longer receive updates which include the updated set of worldwide time zones and daylight saving offsets.

More information than you’ll care to remember is available in KB 914387, How to configure daylight saving time for Microsoft Windows operating systems.


* – an added twist: New Mexico, today in the Mountain time zone, would move in the current proposed legislation to the central time zone and be known as “mountain daylight savings time.”

** – Feb 9, 2015: Latest reports indicate Senate Resolution 1 died in committee.


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