Stripes of solstice daylight

The summer solstice occurs today at 9.24am BST. It's the day of the year with the earliest sunrise and the latest sunset, hence the greatest length of daylight. If you check when that sunrise is you get a single time for London... my diary says 4.43am. If you check when that sunset is you get a single time for London... my diary says 9.21pm. But it's not quite as simple as that because London is a large city approximately 35 miles wide and 28 miles top to bottom. And that's large enough for sunrise not to be at the same time in Upminster as it is in Uxbridge, indeed you may be surprised quite how large the difference is. The first place in London to see the sun rise this morning was J28 of the M25 near Brentwood at 4.40am. In central London, say at Trafalgar Square, the sun rose two minutes later at 4.42am. The last place in London to see the sun rise this morning was Malden Rushett south of Chessington at 4.44am. That's a four minute difference from one side of London to the other.…