For the past four months, we’ve been on standard time. But overnight Saturday, we’ll turn our clocks ahead one hour at 2 a.m., effectively making it 3 a.m. (So don’t schedule any important meetings at 2:30 a.m., because that time won’t exist Sunday — and is not a great time for a meeting, anyway).

This weekend, most Americans will observe Daylight Saving Time, springing their clocks forward one hour. Modern DST has been happening since 1966. The time change, lasting from mid-March to November, gives us more daylight in the evenings. But those summer nights come at a price, according to Harvard Health.