The Full Moon Lights Up Mother’s Day in 2025

Mother’s Day comes with a cosmic companion this year.

While the United Kingdom (UK) marked Mothering Sunday on March 30, under the quiet skies of a New Moon, many other countries—including the United States, Germany, Italy, and Australia—will celebrate Mother’s Day on May 11, when a Full-ish Moon rises.

In 2025, a bright Moon shines on 486 holidays and observances around the world, and 61 of these are Mother’s Days.

How rare are holidays that fall on a Full Moon?

Mother’s Day Around the World

Although most countries celebrate their mothers on May 11 this year, Mother’s Day is not a fixed global holiday around the world. This special day is observed on various dates, shaped by cultural, historical, and religious traditions.

The United Kingdom celebrates Mother’s Day three weeks before Easter Sunday (as “Mothering Sunday”). Costa Rica celebrates on August 15, Georgia on March 3, Samoa on the second Monday of May, and Thailand on August 12, honoring the Queen of Thailand’s birthday.

Mother’s Day and the Full Moon

The alignment between Mother’s Day on May 11 and the Full Moon happens relatively infrequently due to the differing cycles of the lunar month, which is about 29.5 days, and the calendar month, which can be 31, 30, 29, or 28 days long.

“It’s just a coincidence that, this year, May’s Full Moon falls close Mother’s Day in many countries. But it’s really fun to spot these astronomical coincidences. For example, there’s the Metonic cycle, where—by chance—Full Moons and other lunar phases occur on roughly the same calendar dates every 19 years.”

The fullest Moon on Mother’s Day will be shining over South Sudan (99.8%), followed by Cayman Islands and Honduras (99.7%). The slimmest Moon shines over Mexico (98.0%), and Estonia, Finland, Uganda, and Ukraine (all 98.1%)**.

Your Moon guide for May 2025

Mother’s Moon

Although it has nothing to do with science, the Moon is traditionally seen as feminine across cultures. It often represents nurturing, cycles of life, and fertility.

The Celtic and Old English names for May’s brightest Moon phase are actually Mother’s Moon, but today the Full Moon of May is known as the Flower Moon. How’s that for a fun fact while you’re giving your mother flowers under the Full Moon?

While there’s limited scientific proof that the Moon has a measurable impact on human physiology or behavior, emerging research delving into long-standing lunar myths is uncovering intriguing patterns—hinting that we may only be beginning to understand how the Moon influences our lives.

If nothing else, taking a walk with your mother, while enjoying the full Moon will (hopefully) impact you in a positive way.

This is likely what many people will do in Puerto Rico, where families celebrate Mother’s Day with heartfelt gatherings, delicious home-cooked meals, and expressions of gratitude for maternal love and care. Many enjoy outdoor festivities, from beach picnics to moonlit serenades, making this year’s moonlit celebration even more special.

Full or New Moon Mother’s Days in 2025

This table shows all Mother’s Day holidays in 2025 that are either Full Moon holidays (when the Moon is at least 98% illuminated) or New Moon holidays (when the Moon is less than 2% illuminated).

** When comparing percentages of illumination for all holidays around the world, we take the value of illumination at exactly midnight (00:00:00) in each country’s capital time zone. This might not reflect the exact percentages as seen, for example, during the moonrise in any given location. There will be slight differences between time zones within each country—for example, the illumination in New York and Honolulu. You can see the illumination for each location using our Moon Phase Visualization tool.