As the world turns

Summer solstice is the day that has the longest daylight hours. But the earliest sunrise happens before June 21. Why don’t the earliest sunrise, latest sunset, and longest daylight occur on the same day?

Earliest sunrise, latest sunset, and longest daylight would occur on the same day if we used sundials to tell time. Modern timekeeping devices assume that each day is 24 hours long, but this is an average. Near summer and winter solstice, sunrises are separated by slightly more than 24 hours.