Does the pot have good drainage?

I don't see any black spots on them at all so it isn't a disease. Those all look like lower down interior leaves. Sometimes a rose will let those leaves yellow and fall off if they are no longer providing food to the plant. As the plant gets taller and the newer leaves start to shade those inner bottom leaves they can't get enough sun to produce food. The plant will stop sending them water and nutrients because they are no longer contributing to the health of the plant. Just clean them off the plant and pot and watch it. If they continue to yellow check the water. Both OVER and UNDER watering will cause yellowing leaves.

Thanks. That makes me feel better. I moved it to a more sunny spot with better air circulation. I was hoping it wasn't some weird disease I haven't seen before. :-)

A few of my roses have some yellow leaves just like yours. They are also in pots and have been subjected to intermittent rain lately. I'm thinking they're just overwatered. Mine have good drainage and I tip the pots whenever the bottom tray gets filled with rainwater.

I have so many yellow leaves this year. No so much on the potted ones, but on the ones in the ground. My theory is that they were damaged in the freeze, not enough to kill them outright, but enough to make them slowly turn yellow and die. I spent about one hour yesterday pulling them off some of my roses.