I'm very bad at leveling a picture correctly and I found out the hard way that there is for me a better way than the grid in Photoshop. It's the rulers.
Hit Ctrl+R, this will bring up the rulers. They are visible at the top and left of the picture.
When the rulers are visible you can drag a horizontal/vertical line from the upper left corner of the picture and drag it precisely against a know vertical or horizontal area in the picture. You will see instantly if that part of the picture is leveled. In my opinion It works easier than the grid.
If you check at the light poles at the back, you´ll see they´re leaning to the left, so CW rotation will be needed. You may use the grid when you´re in doubt. I haven´t tried the ruler technique myself.