Milly Alcock as Kara Zor-El with Krypto in Supergirl. It doesn't look like things re going to get much better for Supergirl, as after a disappointing opening weekend, the new DCU movie is expected to drop even further at the box office during its second weekend on the big screen. As reported by Variety, Supergirl is expected to make just $15 million over its second weekend in theaters. That's a 60% decline in ticket sales from its first weekend.