No, it is not a good idea.
Temperatures in my part of southeast England hovered around 20 degrees. While this is not baking hot, it’s still a perfectly respectful summer temperature, for England. If we stop imagining that we are a Mediterranean island with unfortunately poor weather patterns and instead embrace the fact that we are a northerly nation, in line with Norway who get very few really hot days relative to the length of the yearl
It;s perfectly warm enough to stay in summer clothes, so o do that, before the temperature really does plummet.
We definitely need to be making hay while the sun shines and enjoy wearing our summer dresses and sandals! By Autumn though, I’m ready to get those tights and lovely jackets on.