In 1992, the San Francisco Giants almost moved to St. Petersburg, Florida. Before the i’s could be dotted and the t’s crossed, new ownership bought the team and the Giants stayed in their Bay Area. Less than 10 years later, the Tampa Bay area received the Devil Rays.

While their results on the field have been somewhat similar since 2008 (Rays winning %: .552, Giants winning % .526), the two teams couldn’t be more different in regards to stadium experience. Since Oct 1, 2010, the Giants have sold out every game at AT&T Park, while the Rays have had 14 regular season sell-outs total since 2010. The Giants play in a beautiful new ballpark on the water, while the Rays play in a dilapidated 30-year old dome.

There is one other major difference when we look at the Giants and the Rays (besides the fact the Giants did draft Buster Posey):

Last year, of the US-based teams, the Giants had the smallest difference in weekend/weekend attendance; the Rays had the largest. By selling out every game, the Giants maintained an average Monday through Thursday attendance of 41,588 and a Friday through Sunday average of 41,589. An average of one person squeezed in to AT&T Park on the weekends.

Meanwhile, at Tropicana Field, the Rays averaged only 14,297 fans per game Monday through Thursday. This was the lowest average weekday attendance in Major League Baseball. On the weekends, however, the Rays averaged 21,692 fans per game. While still the lowest weekend average in Major League Baseball, the Rays saw a 51.7% average increase in attendance on the weekends.

There are many reasons why the Rays struggle with attendance. Many fans and residents point to the condition of the stadium, the demographics, and lack of mass transit as reason for not going. But one of the biggest and least-discussed reasons is that few people actually live near Tropicana Field. According to Maury Brown’s 2011 research on population, the Rays are dead last in population with a 30-mile radius of their ballpark.

A definite correlation exists between the population living within 30 minutes of a ballpark and the difference between weekend and weekday attendance. With only a few exceptions, teams with a 30-minute radius larger than 2 million have smaller weekend/weekday attendance differences. Teams that play in a population radius of less than 2 million, on the other hand, tend to have higher weekend/weekday differences.

Here is a breakdown of the 2014 MLB attendance:

Only the Chicago White Sox and Washington Nationals have more than 2 million people within 30 minutes of their ballpark and had an average weekend difference greater than 20%. Teams with less than 2 million people within 30 minutes of their ballpark who saw a smaller than 20% difference in average weekday to weekend attendance included the Cardinals, Twins, Rangers, and Marlins. The circumstances behind these fanbases should be studied further.

Looking at the data graphically, it is best to omit the New York teams, as the each can draw from a 30-minute population of over 8 million people, more than double any other team on the list. Removing the Mets and Yankees, we see the following:

On the left side of the chart, we see teams with smaller average weekend-to-weekday attendance difference. Notice they are all above 1.5 million and a majority are over 2 million. As we move right on the chart, the percentage gets higher and the dots trend lower, with the exception of the White Sox, who are the top-right dot. The Rays are also evident, as they are the dot in the lower-right.

Local population is important as they are the pool of fans who can most easily get to the ballpark after a day at the office. These are the fans who can also get home from a 3-hour game at a reasonable time. Having a larger local pool to draw from makes it easier for teams to pack their ballpark during fans’ valuable weekday time. It is easier to fill the average major league ballpark on weekdays when 8 million potential fans live within 30 minutes than when a majority of the area’s 3 million people have to travel over an hour each way.

Weekends, on the other hand, usually allow for more time to travel to the ballpark. Fans also don’t have to rush home to get to sleep before the next work day. Fridays and the rare Sunday night game are the odd exceptions as they have a time crunch on one side of the trip, but not the other.

While they don’t have the largest local population, the San Francisco Giants are doing a great job getting local residents to the ballpark. Fans show up, and they show up every day. (Yes, there are articles disputing exactly how many tickets are actually sold.)

The Tampa Bay Rays, on the other hand, will continue to struggle with attendance as long as they have less than 1 million fans living within 30 minutes of Tropicana Field. This is one of clearest reasons for a move to downtown Tampa, where the Tampa Bay Lightning see weekday/weekend attendance differences of approximately 5%. A move to the center of their market could vastly increase the pool of fans within 30 minutes of a Rays game. Or barring a new stadium in a new location, the Rays could build homes, apartments, and condos in an attempt to surround Tropicana Field with at least one million new neighbors.