Whether you’re pro-Daylight Savings or pro-Standard Time, the science is clear: Switching between the two every year is terrible for human health. So why haven’t we stuck with one system all year? The answer is both scientific AND political.

In January 1974, clocks across the United States sprang forward, with no intention of ever falling back. The policy was introduced by President Richard Nixon as an energy-saving response to the previous year’s oil crisis. Theoretically, later sunsets would help offset energy usage. A two-year evaluation period had begun with the intention to make it permanent.

Clearly, this didn’t happen, and the reasons we still have our biannual clock switch can largely be summed up with one word: Watergate. Permanent Daylight Saving Time lasted only a few weeks longer than Nixon himself. In late September 1974, the month after the president’s resignation, the Senate voted to nix the policy. 

The idea of permanent Daylight Savings quickly faded, in part because federal law prevents states from messing with time and time zones. But over the last decade, the idea has been gaining traction.

If you’d like to see more Popular Science videos, subscribe on YouTube. We’ll be bringing you explainers and explorations of our weird world.

 

2025 PopSci Best of What’s New

The 50 most important innovations of the year