The sun and the clock in Porto (2026)
Porto lies at 8.6°W. Its time zone, UTC+0, is built around the prime meridian (0°). The 8.6° gap between them means the clock runs roughly 35 minutes ahead of the sun: solar noon arrives at about 12:35 rather than 12:00. Under daylight saving the clocks move 60 minutes forward, widening the gap to 95 minutes and pushing solar noon to 13:35.
The longest day of 2026 is 22 June, with 15h 9m of daylight. The shortest is 22 December, with 9h 12m. The swing between them is 5h 56m. This is the latitude band where the difference between summer and winter evenings is most obvious.
The earliest sunrise and the latest sunset do not land on the longest day. In Porto the sun comes up earliest on 15 June at 06:01, while the latest sunset waits until 29 June at 21:11. The equation of time is what separates them: the Earth's elliptical orbit and axial tilt move solar noon back and forth by several minutes over the year.
The sky stays usably light for a while after the sun goes down. In Porto that civil twilight runs about 27 minutes at the equinox, stretching to 34 minutes at the solstice.
Every figure in this section is computed from the city's own latitude, longitude and IANA time zone using NOAA solar algorithms (Spencer, 1971), accurate to about ±2 arcminutes below 65° latitude.