That's the 'chemtrail skies' we usually (almost every day) see over Oxford, mostly to the south taking in the flight paths in and out of Heathrow and Gatwick, for example. Today, as yesterday, there are no such white lines across the sky. It's just a natural blue sky with the odd sparse cloud, just like I remember it from my childhood when I would spend days out playing in fields with my friends.
Today, as yesterday, my mind is lifted, my personality is refreshed, my body feels great.
This is seriously weird.