Key points: The Moon’s gravity produces large ocean tides and much smaller atmospheric and terrestrial tides. When the Moon pulls air into a tiny bulge, particle weight can raise local pressure slightly, which can modestly suppress rainfall. Tidal strength varies with lunar distance and alignment; a supermoon amplifies tides. Contrary to folklore, credible medical studies do not show that full moons increase birth rates.
How the Moon Influences Weather: Tides, Atmospheric Bulges, and the Full‑Moon Myth
Key points: The Moon’s gravity produces large ocean tides and much smaller atmospheric and terrestrial tides. When the Moon pulls air into a tiny bulge, particle weight can raise local pressure slightly, which can modestly suppress rainfall. Tidal strength varies with lunar distance and alignment; a supermoon amplifies tides. Contrary to folklore, credible medical studies do not show that full moons increase birth rates.
12:37, 09.11.2025Science
How the Moon Influences the Weather
This week’s question comes from Morning Brief reader Noah: How does the moon affect the weather?
Jonathan Belles, meteorologist: The short answer is that the Moon has a much larger effect on the oceans than on the atmosphere — but it does cause small, measurable effects in the air and even in the solid Earth.
Most people are familiar with ocean tides, but similar processes occur in the atmosphere and the ground. Geophysicists call the tiny daily flexing of Earth’s crust terrestrial tides, and the atmosphere experiences atmospheric tides. All of these arise from gravity: as the Moon orbits Earth, its pull produces a slight bulge on the side of Earth nearest the Moon and a complementary bulge on the opposite side.
One obvious demonstration of tidal forces is the Bay of Fundy, where tidal ranges reach many feet. The strength of tides depends on distance and alignment. When the Sun, Moon and Earth align at new moon or full moon, their gravitational effects add up and produce stronger "spring tides." A supermoon — when the Moon is nearer to Earth than average — also nudges tides to be higher than usual.
Those same tidal forces produce a tiny atmospheric bulge. When airborne particles (moisture, aerosols) are concentrated vertically, they add weight and slightly raise local atmospheric pressure. Higher pressure tends to suppress precipitation, so the Moon’s effect on rain is real but extremely small and usually masked by much larger weather patterns.
There’s a long-standing myth that more babies are born during a full moon, supposedly because pressure changes might trigger labor. Clinical studies and hospital data generally show no reliable link between lunar phase and birth rates, so this remains an anecdote rather than proven science.
As Belles notes with a wink, people often joke that a full moon brings out odd behavior — and sometimes personal anecdotes like his own early birth persist even when broader data do not support a connection.
Bottom line: The Moon does influence the atmosphere, but the effect is tiny compared with ocean tides and ordinary weather systems. Atmospheric tides can be measured and can slightly affect pressure and precipitation, but they are not a major driver of day‑to‑day weather.
If you have a question for the meteorologists at Weather.com, write to us at morning.brief@weather.com and we may feature it in a future edition.