Breathe in, Breathe Out: Daytime Populations of U.S. Cities

I’m fascinated by some new data out from the U.S. Census Bureau that looks at the daytime population change in various U.S. cities and counties. What is the daytime population? It is  “the number of people, including workers, who are present in an area during normal business hours, in contrast to the resident population present during the evening and nighttime hours.”

Make sense? It is a straightforward idea, but the data itself is intriguing, an empirical example of how cities breathe in and breathe out every working day.

Here are some highlights from the Census Bureau press release:

  • Among medium-sized cities, Greenville, S.C., has a daytime population that is 97 percent higher than its nighttime population. Palo Alto, Calif., increases by about 81 percent, and Troy, Mich., by 79 percent.
  • Among very small places, gains approached 300 percent in Tysons Corner, Va. (292 percent); and El Segundo, Calif. (288 percent).
  • New York City has the largest estimated daytime population, at more than 8.5 million persons. The increase of more than half a million people over the nighttime population is bigger than that found in any other area. However, the 7 percent increase puts New York in the middle of the pack on percentage change among cities with more than a million residents.
  • The second highest numeric daytime increase is in Washington, D.C., where 410,000 workers boost the capital’s population by 72 percent during normal business hours.
  • Other big cities with large daytime gains are Atlanta (62 percent), Tampa (48 percent) and Pittsburgh and Boston (both around 41 percent).
  • One of the most extreme examples of daytime population increase is Lake Buena Vista, Fla., which has almost no permanent residents but swells to an employment center of more than 30,000 people during the day

I did some quick & dirty Excel analysis of the underlying nationwide data, and found some interesting stuff, including that there are twenty or so cities with populations over 100,000 that shrink my more than 30% every working day. Thought-provoking data.


  1. lightreader says:

    I was searching for this info for a little while just did not know what to search for! I live close to NYC and was curious to see how many people cross those bridges everyday to get to work. Def Wonderfully interesting stuff

  2. It’s not that interesting stuff is only in U.S. Remember your Motherland.
    Town of Banff has permanent population of 5000 which grows to more than 30,000 in summer (

  3. Ah, that’s true, but Banff only does that every summer. Consider places like Camp Pendleton, CA, Oak Brook, IL, and Fenton City, MO. All of those places have Banff-like permanent populations of between 4,000 and 10,000, but (according to Census Bureau data) grow and shrink by a staggering 20,000-30,000 residents every working day as workers stampede in and out.