London is 950 miles further north than San Francisco. This difference in latitude has a significant effect on the local times for sunrise and sunset in each city.
The longest day of the year in London has 16 hours and 40 minutes of sunshine whereas the longest day of the year in San Francisco has only 14 hours and 47 minutes.
On the other hand, the shortest day of the year in London is a mere 7 hours and 49 minutes of daylight. The shortest day of the year in San Francisco has 9 hours and 33 minutes of sunlight.
Sunrise
In the summer time, the sun rises at its earliest in London at 4:45 AM.
In San Francisco, however, the earliest sunrise is at 5:45 AM.
Sunset
The differences for sunsets between the two cities are similar. At its earliest, the sun sets in London at 3:51 PM. The earliest sunset in San Francisco occurs at 4:51 PM
You will also notice on each graph that London switches to Daylight Savings Time in the spring one week earlier than San Francisco but that both cities switch back to Standard Time on the same day (October 31, 2004)
I will gladly send a copy of the spreadsheet that contains all these calculations on request.