The fairest hour to put a recurring call across all three, not just the one that suits the West. Drag the marker to test any slot — the map shows who’s in daylight and who takes the hit.
San Francisco, Berlin and Bangalore span United States, Germany and India. It is a common product-engineering corridor joining the US West Coast, continental Europe and India. Because the three cities run from west to east, no single hour sits inside everyone’s working day, so the question is which city takes the stretch.
The fairest recurring slot lands in the early-to-mid afternoon UTC. At that hour Bangalore carries the compromise — a late finish while Berlin stays inside working hours. Spreading the load and minimising the total agree here, so there is no cheaper option that would not fall on one city. The exact time is computed live below and shifts by up to an hour around daylight-saving transitions.
Each city’s core day is 9:00–17:00 (zero cost). Outside it, an hour later hurts less than an hour earlier — staying online past five beats waking before eight — so the penalty curve is asymmetric. Fair minimises the worst-off city first (leximin); Efficient minimises the total. Both land on the working-hours frontier — Fair just refuses to let one city absorb the whole gap.