Personally, I won't ride if I need a jacket. That's when the temperature is in the 30's or low 40's F...with a wind.
Mid to low 60's I'll go with a long-sleeve base layer under a jersey.
Low 60's into the 50's I'll go with a long-sleeve jersey with base layer(s).
Mid 50's into the 40's I'll add long cycling tights to the long-sleeve jersey and base layers.

I just don't like the bulk of a jacket, and if the temperature gets that low, I'm just not that interested in cycling. But that's me.