The date of the longest and shortest day by city depends entirely on latitude. At the June solstice (around 21 June), the Northern Hemisphere tilts toward the Sun, giving cities like Reykjavík over 21 hours of daylight, while places such as Buenos Aires get barely 10 hours. Six months later, at the December solstice (around 21 December), the situation reverses. This guide shows how day length varies across major cities through the year.

How Latitude Shapes Day Length

Day length changes because Earth’s axis is tilted 23.5 degrees. A city’s distance from the equator determines how extreme its seasonal swing is. On the equator, day length stays close to 12 hours year-round. Move toward the poles, and the difference between summer and winter grows rapidly. For example, at the Arctic Circle (66.5°N), the Sun does not set on the summer solstice and does not rise on the winter solstice. At the equator, the longest and shortest day by city is only about 12 hours and 7 minutes, versus 12 hours and minus 7 minutes – barely any difference.

Northern Hemisphere: Long Summer Days, Short Winters

Cities north of the equator see their longest days in June and shortest in December. The higher the latitude, the more dramatic the swing.

  • Reykjavík, Iceland (64°N) – Longest day: nearly 21 hours 55 minutes of daylight on 21 June. Shortest day: about 4 hours 10 minutes on 21 December. The Sun barely rises above the horizon in winter.
  • London, England (51.5°N) – The longest day in London is around 16 hours 38 minutes on the June solstice. The shortest day gives just under 7 hours 50 minutes. The sunrise point moves from about 51° east of north in June to 51° west of north in December.
  • New York City, USA (40.7°N) – Maximum day length is about 15 hours 5 minutes; minimum is about 9 hours 15 minutes. The twilight periods also expand as the Sun’s path below the horizon becomes shallower.
  • Tokyo, Japan (35.7°N) – Longest day: about 14 hours 35 minutes. Shortest day: about 9 hours 45 minutes.

Cities near the Tropic of Cancer (23.5°N) have less variation. Mumbai (19°N) sees about 13 hours 15 minutes at its longest and 10 hours 50 minutes at its shortest. The Sun passes directly overhead around the June solstice.

Southern Hemisphere: The Opposite Schedule

South of the equator, the seasons are reversed. The longest day occurs in December and the shortest in June.

  • Buenos Aires, Argentina (34.6°S) – Longest day (21 December): about 14 hours 25 minutes. Shortest day (21 June): about 9 hours 55 minutes. The pattern mirrors that of a Northern Hemisphere city at similar latitude, like Los Angeles.
  • Sydney, Australia (33.9°S) – The summer solstice brings roughly 14 hours 30 minutes of daylight. Winter solstice gives about 9 hours 45 minutes. The Sun’s arc across the sky is correspondingly higher in December.
  • Cape Town, South Africa (33.9°S) – Similar to Sydney: about 14 hours 20 minutes on 21 December, and 9 hours 50 minutes on 21 June.
  • Santiago, Chile (33.5°S) – Longest day: about 14 hours 25 minutes; shortest: about 9 hours 55 minutes.

Near the Tropic of Capricorn (23.5°S), cities like São Paulo (23.5°S) have less variation – about 13 hours 30 minutes in summer and 10 hours 30 minutes in winter.

Equatorial Cities: Almost No Change

Within a few degrees of the equator, day length barely varies. The longest and shortest day by city in this region differs by only a few minutes.

  • Singapore (1.3°N) – The longest day is about 12 hours 12 minutes (around June solstice). The shortest day is about 12 hours 5 minutes (around December solstice). The Sun rises and sets at nearly the same time every day. In Singapore, twilight also changes very little because the Sun’s path relative to the horizon is almost constant.
  • Nairobi, Kenya (1.3°S) – Similar to Singapore: day length ranges from about 12 hours 7 minutes to 12 hours 12 minutes.
  • Quito, Ecuador (0.2°S) – Practically no variation: day length stays within 12 hours 6 minutes to 12 hours 9 minutes. The sunrise point shifts only about 2 degrees north or south through the year.

The Role of Twilight

Day length as commonly quoted refers to the time the Sun’s upper edge is above the horizon. But twilight – when the Sun is 6 to 18 degrees below the horizon – can extend useful daylight. In high-latitude cities, summer twilight never truly ends. For instance, in Reykjavík around the June solstice, the Sun dips only slightly below the horizon, so the sky never gets fully dark. This is known as nautical or astronomical twilight lasting all night. In winter, the opposite occurs: the Sun stays deep below the horizon, giving very long periods of dark.

If you want to understand the mechanics behind these swings, see our article on why day length changes. For precise day lengths for any location, you can see day length by month on our site.

Using This Information

Knowing a city’s extreme day lengths helps with planning travel, photography, and outdoor activities. For photographers, the golden hour and blue hour shift around the solstices. In summer, the golden hour lasts longer because the Sun’s path is shallow. In winter, the window is shorter but the light may be softer.

For residents, the changing daylight affects mood, sleep, and energy. People in northern cities often use light therapy in winter. In equatorial cities, the constant day length means routine barely changes with the seasons.

The longest and shortest day by city is a simple but powerful indicator of how location shapes your experience of time. Whether you live near the Arctic or the equator, the Sun’s rhythm defines each day.