It blows my mind that no retractable roof was placed on Coors Field when it was built...and Target Field for that matter. If the Twins ever make another World Series, their home games will all be snowed out. And snow isn't unusual to see in Denver all the way through April.
I realize roofs add a lot to construction costs, but both those cities experience enough bad weather to make it worthwhile. Even the freaking inept Marlins were smart enough to add one since it rains half the time in Miami...