Does this occur only in cool, damp spring weather or all season long?

Looks like Japanese Beatles started chewing and dropped over dead.

I can't tell but if Ken is right about JB, then you are going for a hell of a ride. I hate those critters..lol. But we could be wrong.

I'm with Ken, this is exactly how my Courageous rose looks once Japanese beatle season begins. The insecticide won't help either, my only solution is to go outside early evening pluck them off one by one into a bucket of soapy water. This reduces the population til they are gone. These beatles get slugish by early evening and its easy to get them. Sadly I saw some on my neighbors rose yesterday so I know they are heading my way. :(

It does happen all season long, on every bud,
in a sunny, warm location. It's not from Jap beetles. I fought those
devils when living in Ohio.
There's no sign of them here in my new location..................at least not
yet.

When my roses looked like that, I assumed it was thrip damage.

Yep, it is thrips. Gosh how tiny they are. You can barely see the buggers, but they do the work in numbers. Thanks all.