Does Daylight Saving Time Save Any Time?

Each Spring and Fall many of us are reminded to change the batteries in our smoke detectors and carbon monoxide alarms by pairing this activity with the transition from Daylight Saving Time to Standard Time or vice versa.  The easy part is the batteries.  Everyone wants an extra hour of sleep but we have to pay that piper in the Spring we when have to give it back.   This time-shifting is not actually great for our health and can lead to what is called social jetlag.


Not all hours are equal.  Ancient civilizations adjusted daily schedules often diving daylighting into 12 hours regardless of daylight so some hours were longer during spring and shorter during autumn. Romans used water clocks with different scales for different months of the year.  Around the 14th century, time was equalized into civil hours of equal length.  In 1810, Spain issued a regulation that moved certain meeting times up an hour but did not change the clocks while some private businesses would informally change their operating hours in the summer.

Latitude matters

Moving time for higher latitudes such as Scandinavia and Alaska has little impact because the length of day and night changes are more extreme, to begin with, and are already out of phase with what many of us would consider normal working hours.  Similarly, DST has little value in locations near the equator where the days and nights are already pretty equal throughout the year.  The impact also varies according to how far east or west one might be within a time zone.  A more eastern location inside the time zone provides more benefits than locations farther west within the same time zone.

History, Controversy, and Health

Almost from the beginning, DST has been controversial.  Retail, sports, and tourism have favored the change, but agriculture – ironically the very people that proponents claim are the beneficiaries – have generally opposed it.

Daylight saving time was originally proposed in 1895 by the entomologist, George Hudson as a way to collect insects after his “day job”.  Port Arthur, Ontario became the first City to formally adopt DST on July 1, 1908.  During WWI many countries adopted DST to save coal during the war.  Proponents generally argue that it saves energy and promotes outdoor leisure activities making it good for physical and psychological health, reduces traffic accidents and crime, and is just good for business.

Opponents counter that Daylight Saving Time is less aligned with human circadian biology. An 18% increase in adverse medical events related to human error has been documented in the week after switching to Daylight Saving Time.  Traffic fatalities increase by as much as 6% in the first few days following the change to Daylight Saving Time.

On average 55% of adults feel extremely or somewhat tired after the spring change with a loss of 1-hour  sleep.  In a recent survey of more than 2,000 adults, 63% support the elimination of seasonal time changes.  DST disrupts travel, billing, record keeping, medical devices, heavy equipment, and sleep patterns.  Negative, short-term consequences can be correlated to increased risk of heart attack or stroke,  hospital admissions, sleep loss, stress, and worst of all, suicide.

Lacking the promised energy savings there may be little evidence to support the practice.

Permanent DST?

In the US, Florida, Washington, California, and Oregon have passed legislation to remain on Daylight Saving Time permanently, but this requires Congressional approval and with the current environment in Washington, this is unlikely.  Without a federal law, states cannot enact a permanent DST.  They can only opt-out of DST, as Arizona has, but they cannot opt-out of standard time.  In 1971, the UK abandoned permanent DST because of complaints about winter sunrise time.

What to do?

For now, there is little to be done, but make sure you have plenty of batteries to load up your smoke detectors, rely on your digital devices to reset themselves, and remember to change those few analog devices you might still have.  Now how do I change that clock in my car?