The last sunset of the year always comes after the summer solstice, although the exact date of the last sunset depends on your latitude. Further north in Seattle, the last sunset occurred around June 25. Further south, in Mexico City or Hawaii, the last sunset will not occur until early July.
Do you want to know your date of the last sunset? Try this custom sunrise / sunset calendar.
The last sunset is coming after the summer solstice because the day lasts more than 24 hours at this time of year.
For several weeks, around the June solstice, the day (measured by the successive returns of the midday sun) is almost 1/4 minute more than 24 hours. Therefore, the midday sun (solar noon) comes later by the clock in late June than on the June solstice. Therefore, the sunrise and sunset times also come later by the clock, as the table below helps explain.
For Denver, Colorado
|Date||dawn||Noon (solar noon)||Sunset||Hours of the day|
|June 20th||5:32 am||1:01 pm||8:31 pm||14h 59m 15s|
|June 27th||5:33 am||1:03 pm||8:32 pm||14h 57m 50s|
If the axis of the Earth were kept upright while our world surrounded the sun, and if, in addition, the Earth remained at the same distance from the sun throughout the year, then the time of the clock and the time of the sun would always be agree. However, the Earth's axis is titled 23.44 degrees outside the vertical, and our distance from the sun varies by approximately 3 million miles (5 million km) throughout the year. On and around the equinoxes, solar days are short 24 hours, but on solstices, solar days are plus 24 hours
The last sunset always reaches or near June 27 at mid-northern latitudes each year.
In mid-north latitudes, the later hours for solar noon one week after the summer solstice is more substantial than the change in daylight hours. Since daylight hours today (June 27) are almost the same as a week ago (on the solstice of June 20), the time after the clock for solar noon today also gives us a little later than sunrise and sunset.
Bottom line: Why don't the last sunsets come on the longest day (the solstice)? Simply put, it is a discrepancy between the sun and the clock. Therefore, for mid-northern latitudes, the last sunsets always come in late June.
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