The sun isn’t always a fixed distance from earth. It’s closest in January
Forgive me if I'm just missing a joke, but it's not about the distance, it's about the angle. In the summer the angle means the days are longer, and sunlight travels through less atmosphere (and is therefore less attenuated) before it reaches you and gives you sunburn.
Thanks, I was finding it pretty astounding as well, so it'd make sense if it was the misinterpretation you've described. Maybe send the Guardian a message noting it so they can check?