The end of daylight time this Sunday means an extra hour of sleep for most Canadians. It also means that some of us will once again be wondering why we set our clocks back one hour in November and an hour forward in March, and whether the time shifts are really necessary.

Here’s what you need to know before we switch back to standard time.

What time do the clocks fall back this weekend?

Daylight saving time ends at 2 a.m. Sunday. That’s when clocks need to be set back to 1 a.m.

On March 12, 2017, daylight time will begin again at 2 a.m. Clocks will spring forward one hour so that we can enjoy more sunlight in the evenings.

Does everyone in Canada observe daylight time?

No. Saskatchewan has not observed daylight time since the 1960s. Some pockets of the country, including communities in Ontario, British Columbia and Nunavut, also shun the time shift.

Why do we have daylight saving time?

Germany was the first country to adopt the system during the First World War, with the goal to minimize the use of artificial lighting and save fuel. Many other countries, including Canada, the United States and the United Kingdom, followed suit.

DST letter

The modern-day observance of DST in Canada has been aligned with the time shifts in the U.S. In 2005, then-president George W. Bush signed the Energy Policy Act into law, which extended daylight saving time. The start of DST was changed from the first Sunday in April to the second Sunday in March. Canada followed suit to ensure that the time shifts did not disrupt business dealings with its biggest trade partner.

Why is DST so controversial?

Daylight Saving Time

Over the years, various groups have expressed concern about the negative effects of the time shifts on our health and the economy.

Several studies have suggested that DST leads to higher incidents of traffic and workplace accidents, as well as reduced productivity in the days after the shift.

The time shift has also been linked to negative health effects. A study published in the New England Journal of Medicine in 2008 found that the number of heart attacks significantly increased for the first three weekdays after the transition to daylight saving time.

A more recent study from Denmark found that changing from daylight saving time to standard time increases the number of cases of serious depression.

There is a growing movement in the United States and Europe to either keep daylight time year-round or abandon it entirely. About 10 U.S. states have proposed legislation to kill the time shifts. Several Canadian communities have also launched petitions to abolish DST over the years.

How can adults adjust?

Dr. Charles Bae at the Cleveland Clinic's Sleep Disorder Center says the extra hour this weekend can help sleep-deprived adults, but he cautions against taing the opprtunity to spend an extra hour in bed on Sunday morning. Instead, he told CTV News Channel, get up at your normal time, go to bed when you're tired and then stick to a regular routine.

"Now is the time to really focus on getting back to our regular sleep schedule."

How families with children can adjust

Experts have long warned that the beginning and end of daylight saving time can seriously disrupt children’s sleep patterns.

Last year, one expert provided these parenting tips in an interview with CTVNews.ca:

Make sure children's rooms are dark

Use a white noise machine to mask external sounds

For older children, use a toddler clock that visually shows the time so they know it's not time to leave their room, even if they feel awake