Turn dusk to night (FCP)
 

I'm in need of an effect that will turn a dusk shot into a night shot. We shot on a soccer field with the lights, so there are lights on the players, but the "game" started at 8:45PM, and the sky isn't as dark in shot 1 as it is in shot 7. I'm doing this for work, and they don't have after effects on this computer. I've never done anything like this in FCP, and it's irritating because I know there HAS to be some way.

Also, The lighting on the players is fine, and I don't want to change that. Only the sky.

Yes, you can absolutely do this in FCP without AE; using the 3-way Color Correction filter you can selectively alter any single color value independent of anything else on the screen. You can also use masking/layers also.

Try the online tutorials on Apple.com, Lynda and Digital Juice to really understand the process.