Kevin Pelton, in a post for Basketball Prospectus, develops the concept of effective height.
Part of the definition comes from taking the height of each player on the team and weighting those heights by the number of minutes played. This insures that if a team has a big player that doesn't play much, that player's minutes don't add anything significant to the team's weighted height.
However, Pelton is looking at NBA teams and not WNBA teams. I decided to copy what he did for the WNBA. Here are the effective team heights for the league and for individual teams in the 2009 WNBA season:
Silver Stars: 70.81
Let's look at some of the outliers.
Atlanta's team is so big because Erika de Souza and Sancho Lyttle eat up a lot of minutes in the post - both of those players were All-Stars. Every player taller than 6 feet who contributes significant minutes is going to give your team better than average height. Chamique Holdsclaw is 6'2", Angel McCoughtry is 6'1" and only Coco Miller and Ivory Latta threatened to bring those numbers down - but neither played significant minutes.
As for the Silver Stars, the 6'1" Sophia Young and the 5'6" Becky Hammon played the most minutes on that team - Hammon's height brings San Antonio's effective height way down. (Is Hammon the best short player in the WNBA?) Of the six players of the Silver Stars who were taller than 6 feet, Ruth Riley played the most minutes at 650. Compare this to Atlanta, where de Souza and Lyttle played over 900 minutes each.
Does height correlate with winning? And if it does, by how much?
Pelton's analysis on the NBA correlated height with winning percentage at a factor of 0.190 - it's not a strong correlation, but it has some slight significance. To put it in Pelton's words, "you can't guess a team's record very well from its height" - although having a tall team certainly never hurts you.
Maybe height has a weaker correlation to winning in the WNBA - after all, the range of heights is smaller among women than among men, so having one extra inch of height on another player doesn't make you all that much taller. After all, look at the Mercury - they were the W's 11th tallest team in 2009, and they won it all.