Perpetually dark mornings during late fall and early winter are a common experience. This phenomenon results from the Earth’s orbital mechanics, which cause the sun to rise later as the Northern Hemisphere tilts away from the sun. The mornings continue to grow darker well past the shortest day of the year, leading many to wonder when the clock time for sunrise will finally begin to shift earlier. Understanding this turnaround requires examining the precise daily timing of the sun’s appearance, not just the total length of daylight.
The Astronomical Turning Point
The annual cycle of changing daylight is anchored by the Winter Solstice, occurring around December 21st in the Northern Hemisphere. This moment marks when the North Pole is tilted farthest from the sun, resulting in the shortest period of total daylight. Following the solstice, the total duration of sunlight begins to increase immediately, signaling the slow return toward longer days.
The initial increase in day length is measured in mere seconds and is distributed between the morning and evening. This added daylight is not split evenly between an earlier sunrise and a later sunset, leading to a period of asymmetry. Although the total length of the day increases immediately, the clock-time change for sunrise lags significantly behind the shift for sunset.
Why Sunset Changes Before Sunrise
Evenings begin to get lighter—with sunset occurring later—several weeks before the mornings do due to the Earth’s elliptical orbit and axial tilt. The Earth’s path around the sun is an ellipse, causing its orbital speed to vary. The planet moves fastest when closest to the sun, a point called perihelion, which occurs in early January.
Because the Earth is moving faster in its orbit during this period, it must rotate slightly further on its axis for the sun to return to the same position, making the true solar day slightly longer than the 24-hour clock day. This variation between “sun time” and “clock time” is described by the Equation of Time. The combination of the planet’s varying speed and its 23.5-degree axial tilt creates an imbalance in the clock times of sunrise and sunset relative to the solstice.
The solar noon, the moment the sun reaches its highest point, occurs progressively later by clock time through December and early January. This later solar noon pushes both the sunrise and the sunset times later each day. Since the total amount of daylight is increasing after the solstice, that extra daylight is added to the evening. This gain overpowers the later solar noon effect on the sunset time, causing sunset to start shifting later in early December.
In the morning, the later solar noon effect continues to push the sunrise time later. For a few weeks after the shortest day, the clock time for sunrise is still being shifted later by orbital dynamics, overriding the small daylight gain. This results in the paradoxical experience where the earliest sunset occurs well before the shortest day, and the latest sunrise occurs well after it.
Pinpointing the Morning Turnaround
The earliest sunset generally occurs in the Northern Hemisphere around the first or second week of December, often between December 7th and 10th for mid-latitudes. At this point, the evenings have already begun their slow march toward lighter times, even though the total length of the day is still decreasing toward the solstice.
In contrast, the mornings continue to darken until the latest sunrise of the year, which occurs around two to three weeks after the Winter Solstice. For mid-latitude locations, the latest sunrises are usually recorded between January 3rd and January 7th. After this date, the increasing daylight of the post-solstice period finally overcomes the orbital mechanics pushing solar noon later, and the sunrise time begins its steady shift earlier.
The Impact of Human Timekeeping
The relationship between sunrise and sunset times is complicated by the implementation of Daylight Saving Time (DST). The dates mentioned for the earliest sunset in December and the latest sunrise in January are based on Standard Time. These dates represent the true, natural astronomical cycle of the sun.
The most dramatic, sudden change in morning light is artificial, occurring when clocks are moved forward one hour in the spring. This switch to DST instantly shifts the perceived sunrise time a full 60 minutes later by the clock. This dramatic, one-time jump often masks the slow, gradual astronomical change that has been occurring naturally since the latest sunrise in mid-January.
In regions that do not observe DST, the shift to earlier sunrises after mid-January is a smoother, more gradual change that is more directly observable from day to day. For most people, the true turning point toward earlier mornings is a subtle astronomical victory that is often overshadowed by the major, artificial clock changes mandated by human timekeeping systems.