The moon can influence the rainfall on Earth, scientists have found.

When the moon is high in the sky, lunar forces create bulges in the planet's atmosphere that change air pressure to make rainfall lighter.

Rain is less likely to fall when this bulge is at its highest. Since the full moon is always highest at midnight, that is when there is the least risk of a shower.

Tsubasa Kohyama, a doctoral student at the University of Washington in Seattle, was studying atmospheric waves when he noticed a puzzling oscillation in the air pressure.

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He and his co-author John Wallace, a professor of atmospheric sciences, spent two years tracking the phenomenon.