Very cold and damp...and sarcastic
We went a couple years ago in the fall. 2 weeks of England, Wales & Scotland: 3 rain days. Definitely do the scotch distilleries. They usually give a couple drams at the tours. Have a designated driver.
It depends what you call cold. I have spent a lot of time in the UK and it is not nearly as cold in winter as the parts of the US where I’ve lived (West/Midwest)
You will very rarely have a day in England when the temperature stays below freezing. Scotland is colder for sure.
Mind you, you can feel very cold if you get wet and can’t dry off.