How Many Full Moons Per Month in 2025
In 2025, most calendar months have one full moon, but a few months contain two full moons, which is often called a blue moon. The lunar cycle lasts about 29.5 days, so the timing shifts each year and can place a second full moon inside a single month. This pattern affects monthly planning for events, travel, and cultural observances tied to lunar calendars. For a detailed 2025 full moon calendar, see the timeanddate.com full moon dates page.
The first full moon of 2025 occurs on January 13, and the last full moon of the year lands on December 11. Between those dates, there are 13 full moons distributed across the 12 months, meaning at least one month will host two full moons. The exact month that gets a second full moon changes every year because the calendar year is slightly longer than 12 lunar cycles. This mismatch is why the phrase once in a blue moon exists and why monthly counts can vary.
Months With Two Full Moons in 2025
In 2025, August is the month with two full moons, with the first on August 1 and the second on August 31. The second full moon in a single calendar month is commonly referred to as a blue moon, even though the moon does not actually change color. This occurrence happens because the first full moon arrives early in the month, leaving enough time for a second cycle before the month ends. The next month with two full moons after August 2025 will not occur until 2026.
A double full moon month can influence cultural events, religious observances, and financial market folklore, even though it has no direct causal effect on asset prices or economic data. For example, some traditional calendars use the second full moon to set dates for festivals or harvest-related activities. Investors and planners who track lunar phases sometimes reference these dates when scheduling or analyzing seasonal patterns. The concept is widely covered by sources such as the Forbes article on blue moons and calendar quirks.
Why the Number of Full Moons Varies by Month
The number of full moons per month depends on the interaction between the 29.5-day lunar cycle and the 30 or 31-day calendar month. February, with only 28 days in common years and 29 in leap years, is the only month that can completely miss a full moon, which happened in February 2018 and will happen again in February 2037. All other months have at least one full moon, and longer months like January, March, May, July, August, October, and December are more likely to host two full moons in a given year.
Space agencies and astronomy organizations publish full moon calendars years in advance using precise orbital calculations from sources like NASA. The exact timing of each full moon is expressed in Coordinated Universal Time and then converted to local time zones for public visibility. For a reliable, science-based schedule of moon phases, see the NASA Goddard Space Flight Center lunar phases page.