Each year in March, clocks across most of the United States (and Canada) move forward one hour as Daylight Saving Time begins. The shift marks a seasonal turning point, trading darker mornings for brighter evenings as spring approaches.
Daylight Saving Time starts at 2 a.m. local time on the second Sunday in March. At that moment, clocks jump ahead to 3 a.m., and we lose one hour of sleep. In return, sunset occurs an hour later on the clock that evening.
The time change does not change the amount of daylight Earth receives. Instead, it shifts how daylight aligns with our schedules. After the switch, sunrise and sunset both occur later by the clock. The immediate effect is most noticeable in the evening, when additional evening light extends outdoor time after work or school.
In DC, the transition to Daylight Saving Time arrives just as days are lengthening rapidly ahead of the spring equinox. By mid-March, the region is gaining 2½ minutes of daylight per day.
The adjustment can temporarily disrupt sleep patterns. Research has shown that the sudden loss of an hour may lead to grogginess or reduced alertness early in the week following the change. You can ease the transition by shifting bedtime slightly earlier in the days leading up to the time change.
Daylight Saving Time remains in effect until early November, when clocks “fall back” one hour and standard time returns. While debates periodically arise about making Daylight Saving Time permanent, for now the biannual clock changes continue. The current daylight saving time schedule has been observed since 2007.
For many, the start of Daylight Saving Time signals the unofficial arrival of spring, as longer evenings and milder temperatures coincide with the return of outdoor activities. And even though mornings are darker at first, it takes just over a month to recoup the lost hour of morning light, as sunrise continues to move earlier. Meanwhile, we continue to benefit from increasingly later sunsets as spring progresses.
A good time for a few quick reminders
The time change is also a useful seasonal cue to tackle a few household tasks:
- Test smoke and carbon monoxide alarms and replace batteries if needed.
- Change HVAC filters to improve efficiency heading into spring.
- Check outdoor lighting and timers after resetting clocks.
- Review emergency kits: replace expired items and refresh water supplies.
- Schedule spring yard cleanup or inspect gutters and downspouts after winter.
- Reset irrigation systems and check for leaks before the growing season begins.
