Sep 28, 2023 - News

Seattleites may feel 2023's last supermoon, even with clouds

This month's full moon will be the last of the year's four supermoons. Photo: Bodo Marks/picture alliance via Getty Images

Overcast skies will almost certainly prevent Seattleites from seeing the fourth and final supermoon of 2023, but that doesn't mean people won't feel its effect.

Driving the news: The harvest moon will be at its fullest between Thursday night and Friday morning.

Why it matters: Studies over the last couple of years have shown that people have a harder time sleeping around the time of the full moon, especially in the days leading up to it.

  • These changes were observed in urban and rural settings — from Indigenous communities in northern Argentina to college students in Seattle — according to a 2021 study led by University of Washington researchers and published in Science Advances.
  • But, surprisingly, the impact persists even if people cannot actually see the moon, University of Washington scientist and sleep expert Horacio de la Iglesia said.

What they're saying: "We see the effects in Seattle regardless of the weather," de la Iglesia told Axios this week. "We still don't know how it happens, but we are convinced that it is not from seeing the moonlight itself."

  • The exact reason for human sensitivity to the moon's cycle isn't understood, said de la Iglesia. But he theorizes that early humans worked and socialized later in the night when the moon was bright and that has now become a built-in trait.

What to do: The influence is strongest before the full moon and will begin to dissipate by Friday night, de la Iglesia said. But for now, he said, avoid caffeine, screen time and other things you already know interrupt good sleep habits.


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