lite rust on rotors

[svx1999]

Hello Guys/gals

I've gota question about Rust appearing on rotors. I started noticing rust forming on my rotors if I odn't drive the car for a few days. I wasn't sure if that was normal or not.

They are Suby Rotors that I had Cryo Treated. I figured about after the first stop, most of the rust is knocked off. just wasn't sure if it should form so quickly....
or maybe I'm just being dumb......

someone let me know if this is normal or not..... I've noticed it on other cars but they had been sitting for serveral months.
thanks
SVX1999