
What Is the Most Common Birthday Month and Year in the U.S.?
Have you ever noticed that there are months where there are birthdays within your circle practically every day? Here at Kremp Florist, we’re passionate about birthdays, so we’re happy to present to you an analysis of the 29,882,341 recorded births (between 2016 and 2023) in the CDC WONDER Natality database to determine the most common birthday month. Any guesses? We’ll unwrap that in a bit! As frosting for this data-delicious birthday cake, we dipped into nearly 16 million U.S. Census American Community Survey responses to find the most common birth year in every state as well. To add sprinkles on top, we also found the average and median age by state using this abundance of data. Which states would you guess are the oldest and youngest? Without further ado, let’s get this party started!
What Is the Most Common Birthday Month?
The most common birthday month by far is August, reigning supreme in 45 out of 50 states. Why is August the most common birth month most common birth month? If you count back nine months from August, you would be in the late fall and early winter, making November and December the most popular times to conceive. There are a few factors at play here:
Season’s Greetings
Chilly temperatures outside mean more time and desire for closeness indoors. The festive period between Thanksgiving and New Year’s Day is packed with quality time, relaxation, celebration, and just all-around joyful spirits; these happy feelings are often the perfect ingredients for more merry intimacy.
Fertility Boosts
There may also be science at play; some research suggests that sperm quality may be higher in winter and lower in summer because sperm prefer cooler environments (extreme heat reduces sperm quality, quantity, and mobility). The time of year also affects female fertility. Shorter fall and winter days boost melatonin levels, which help you sleep within your natural circadian rhythm, and this may indirectly support the stability of fertility hormones like prolactin and luteinizing hormone.
Practicality and Human Nature
Of course, every pregnancy is different, and it’s impossible to predict exactly how it will unfold. But for many people, the ideal time to have a baby is during the summer (which also happens to be the most unpleasant time to be pregnant). There are no major holidays to plan around, there’s less risk of seasonal illnesses, and you might even have more time off already built into your annual schedule. The desire to conceive in winter and give birth in summer might also be evolutionary; in many climates, a newborn has a better chance of survival if it avoids challenging winter conditions during infancy. July is a close second for the most common birth month, further supporting the theory that these factors influence the most common birthday month.
What Is the Most Common Birthday in the United States?
The most common birthday in America is actually Sept. 9: Surprisingly, it’s not in August. According to birth data from the National Center of Health Statistics and the Social Security Administration, an average of 12,301 births have happened on Sept. 9 each year over the past 20 years. If you’re a Sept. 9 baby, you share a birthday with Adam Sandler, Hugh Grant, Otis Redding, Michael Bublé, Leo Tolstoy, and KFC’s founder, Colonel Harland Sanders himself! That’s a whole lot of talent (and flavor).
Which U.S. State Has the Oldest Population?
The oldest U.S. state, according to our research, is Maine; the median age of Maine residents is 55. Why does Maine have an older population? According to Maine.gov, the golden age of the state “reflects broader national and global shifts, where populations are living longer and birth rates are declining.”
Which U.S. State Has the Youngest Population?
Which U.S. state has the youngest population, according to our findings? The youngest U.S. state is Utah, with a median age of 37. Why are there so many young people in Utah? A major contributing factor is that Utah has the highest birth rate in the nation. The University of Utah Kem C. Gardner Policy Institute describes Utah’s unique demographic profile as “youthful, aging, urban, and more racially and ethnically diverse.” However, much like the rest of the country, average ages are increasing across the board.
Kremp Loves Birthdays!
We hope you enjoyed learning about the most common birthdays and birthday months in America. No matter how common a birthday is, we believe in treating each one like a special occasion. We offer a delightful selection of birthday flowers perfect for celebrating someone you care about. Of course, flowers aren’t the only way to bring an uplifting aroma to their special day; birthday flower candles are sure to please! Know someone who is quite proud of their birthday month? You might also send them one of our precious birthstone bears or a pair of charming birthstone earrings.
What Are the Most Common Birth Months and Years in the United States?
We’ve identified the most common birth months and birth years among living individuals in each U.S. state by analyzing 15,912,392 U.S. Census American Community Survey (ACS) responses and 29,882,341 birth records from the Centers for Disease Control (CDC) WONDER Natality database. Here are the results:
What Is the Most Common Birth Month and Year in Every State?
State | Most common birth month by state | Most common birth year by state | Most common age by state (estimated) | Percentage of people with most common birth year |
Alabama | August | 1958 | 67 | 1.62% |
Alaska | August | 2010 | 15 | 1.59% |
Arizona | August | 1959 | 66 | 1.49% |
Arkansas | August | 1959 | 66 | 1.55% |
California | August | 1990 | 35 | 1.41% |
Colorado | August | 1990 | 35 | 1.47% |
Connecticut | August | 1961 | 64 | 1.61% |
Delaware | August | 1957 | 68 | 1.93% |
Florida | August | 1960 | 65 | 1.62% |
Georgia | August | 1964 | 61 | 1.50% |
Hawaii | August | 1953 | 72 | 1.53% |
Idaho | August | 2005 | 20 | 1.52% |
Illinois | August | 1958 | 67 | 1.53% |
Indiana | August | 1959 | 66 | 1.53% |
Iowa | August | 1960 | 65 | 1.60% |
Kansas | August | 1958 | 67 | 1.56% |
Kentucky | August | 1958 | 67 | 1.54% |
Louisiana | August | 1956 | 69 | 1.61% |
Maine | July | 1955 | 70 | 1.92% |
Maryland | August | 1960 | 65 | 1.55% |
Massachusetts | August | 2002 | 23 | 1.63% |
Michigan | August | 1958 | 67 | 1.75% |
Minnesota | August | 1960 | 65 | 1.68% |
Mississippi | August | 1960 | 65 | 1.62% |
Missouri | August | 1960 | 65 | 1.58% |
Montana | July | 1954 | 71 | 1.80% |
Nebraska | August | 1960 | 65 | 1.56% |
Nevada | August | 1959 | 66 | 1.51% |
New Hampshire | July | 1959 | 66 | 1.93% |
New Jersey | August | 1963 | 62 | 1.59% |
New Mexico | August | 1954 | 71 | 1.66% |
New York | August | 1960 | 65 | 1.54% |
North Carolina | August | 1960 | 65 | 1.52% |
North Dakota | August | 1960 | 65 | 1.64% |
Ohio | August | 1958 | 67 | 1.60% |
Oklahoma | August | 1961 | 64 | 1.45% |
Oregon | August | 1953 | 72 | 1.56% |
Pennsylvania | August | 1957 | 68 | 1.67% |
Rhode Island | August | 2002 | 23 | 1.88% |
South Carolina | August | 1957 | 68 | 1.61% |
South Dakota | July | 1956 | 69 | 1.59% |
Tennessee | August | 1957 | 68 | 1.54% |
Texas | August | 1961 | 64 | 1.40% |
Utah | August | 2004 | 21 | 1.75% |
Vermont | August | 1954 | 71 | 1.85% |
Virginia | August | 1960 | 65 | 1.50% |
Washington | August | 1957 | 68 | 1.43% |
West Virginia | August | 1956 | 69 | 1.72% |
Wisconsin | August | 1960 | 65 | 1.75% |
Wyoming | May | 1957 | 68 | 1.71% |
What Is the Average and Median Birth Year in Every State?
State | Average birth year by state (rounded to the nearest year) | Average age by state (estimated) | Median birth year by state | Median age by state (estimated) |
Alabama | 1978 | 48 | 1976 | 49 |
Alaska | 1983 | 42 | 1984 | 41 |
Arizona | 1978 | 47 | 1978 | 47 |
Arkansas | 1978 | 47 | 1977 | 48 |
California | 1980 | 45 | 1980 | 45 |
Colorado | 1980 | 45 | 1980 | 45 |
Connecticut | 1977 | 48 | 1976 | 49 |
Delaware | 1975 | 50 | 1972 | 53 |
Florida | 1975 | 50 | 1972 | 53 |
Georgia | 1979 | 46 | 1979 | 46 |
Hawaii | 1977 | 48 | 1977 | 48 |
Idaho | 1980 | 45 | 1981 | 44 |
Illinois | 1979 | 46 | 1978 | 47 |
Indiana | 1979 | 46 | 1979 | 46 |
Iowa | 1978 | 47 | 1978 | 47 |
Kansas | 1979 | 46 | 1979 | 46 |
Kentucky | 1979 | 46 | 1978 | 47 |
Louisiana | 1978 | 47 | 1977 | 48 |
Maine | 1974 | 51 | 1970 | 55 |
Maryland | 1979 | 46 | 1978 | 47 |
Massachusetts | 1978 | 47 | 1978 | 47 |
Michigan | 1977 | 48 | 1975 | 50 |
Minnesota | 1978 | 47 | 1977 | 48 |
Mississippi | 1978 | 47 | 1977 | 48 |
Missouri | 1978 | 47 | 1978 | 47 |
Montana | 1977 | 48 | 1975 | 50 |
Nebraska | 1979 | 46 | 1979 | 46 |
Nevada | 1979 | 47 | 1978 | 47 |
New Hampshire | 1976 | 49 | 1973 | 52 |
New Jersey | 1978 | 47 | 1977 | 48 |
New Mexico | 1977 | 48 | 1976 | 49 |
New York | 1978 | 47 | 1978 | 47 |
North Carolina | 1978 | 47 | 1977 | 48 |
North Dakota | 1979 | 46 | 1979 | 46 |
Ohio | 1978 | 47 | 1977 | 48 |
Oklahoma | 1980 | 45 | 1981 | 44 |
Oregon | 1978 | 48 | 1977 | 48 |
Pennsylvania | 1977 | 48 | 1975 | 50 |
Rhode Island | 1977 | 48 | 1976 | 49 |
South Carolina | 1977 | 48 | 1976 | 49 |
South Dakota | 1979 | 46 | 1979 | 46 |
Tennessee | 1978 | 47 | 1978 | 47 |
Texas | 1981 | 45 | 1981 | 44 |
Utah | 1985 | 40 | 1988 | 37 |
Vermont | 1975 | 50 | 1972 | 53 |
Virginia | 1979 | 46 | 1979 | 46 |
Washington | 1979 | 46 | 1980 | 45 |
West Virginia | 1976 | 49 | 1974 | 51 |
Wisconsin | 1977 | 48 | 1975 | 50 |
Wyoming | 1979 | 46 | 1979 | 46 |
Methodology:
To determine the most common birth year in every state, we analyzed 15,912,392 individual U.S. Census American Community Survey (ACS) responses that were collected between 2019 and 2023. The U.S. Census ACS data was sourced from IPUMS.org and was analyzed using Google Colab and Python. To determine the most common birth months, we analyzed data from the CDC WONDER Natality database that was collected for all 29,882,341 recorded births that took place in the United States from 2016 to 2023.
Notes:
- The most common birth months and years are approximations based on the largest and most authoritative public datasets available.
- Birth data on specific days of the month is not made available to the public for privacy reasons.
Sources:
- IPUMS USA (https://usa.ipums.org/usa/)
Steven Ruggles, Sarah Flood, Matthew Sobek, Daniel Backman, Grace Cooper, Julia A. Rivera Drew, Stephanie Richards, Renae Rodgers, Jonathan Schroeder, and Kari C.W. Williams. IPUMS USA: Version 16.0 [dataset]. Minneapolis, MN: IPUMS, 2025. (https://doi.org/10.18128/D010.V16.0) - U.S. Census (https://data.census.gov/)
- Google Colab (https://colab.research.google.com/)
- Python (https://www.python.org/)
- CDC WONDER Natality database (https://wonder.cdc.gov/natality.html)