Desktop Clock
Sunrise Sunset
Overview
View when the sun will rise, set, and more. You can see dusk, dawn, noon, nadir, golden hour, and more times, with complete descriptions of each. You can also see how many hours of daylight are available and how many hours until sunrise or sunset. You can enter any date, any location, and any timezone and instantly get everything you need to know. There's also an easy one click button to use the current date, location, and timezone. Finally, there's a table of future days and their sunrises, sunsets, and more, and it's fully customizable in settings.
Enter Date, Location, and Timezone
The time the sun is at a specific position (such as sunrise or sunset) varies not just with where you are, but what day you choose. Sunrise Sunset allows you to enter a custom date, and also enter a timezone. For example, you may be in London wanting to know what time the sun will set in New York, but want the time formatted in London time. You can enter the date, location, and timezone to use at the top of the page. There is a button at the top that will set the date to today, the timezone to your current timezone, and use your current location. When setting the day to today, the app will remember that and update to use the current day on future days. You can individually change any of these values by clicking the pencil icon next to them. The local time is also shown for your convenience. This display can be toggled by changing the secondary display.
Change Latitude and Longitude
If you prefer to not use your current location, you can enter a custom latitude and longitude by clicking the pencil icon next to "Location". If you want to select a city, you can search for a city at the bottom to use its latitude and longitude.
Primary Display
The primary display shows the sunrise and sunset times as well as direction of the sun. It will also show you the daylight duration and times for other sun positions such as solar noon, golden hour, and more. Click the "About" button there to view a table of information about each sun time and what angle the sun is at for that time. You can toggle this view by changing the primary display.
Sun Table
Below the primary display, there is a table that displays more sun positions and what time they will occur in future days. You can customize or hide this display by opening settings and going to "Sun Table". You can choose which properties to display and how many rows of days you would like to see. If you select a different date, then these times will update and show that many days after that date and what time the sun will be at each of the positions you have selected. You can also see the daylight duration for each of these days.
Why does December have the longest days?
December actually has shorter days in terms of daylight duration in the northern hemisphere due to the tilt of Earth's axis relative to its orbit around the sun. The Earth's orbit is eliptical, not circular, so sometimes it's closer to the sun. When it's closer to the sun, it moves faster (due to gravity), so the Earth has to rotate slightly (0.033 degrees) farther before the sun comes back overhead. Also, Earth's axis is tilted, which means at the time of year when the tilt points towards or away from the sun, narrower slices of longitude are aimed at the sun. As the Earth moves in orbit, it rotates slightly (0.088 degrees) farther in order for a particular line of longitude to catch up with the sun. More rotation takes more time, making the days longer in December. The longest day of the year is December 22, which is 30 extra seconds. This is when measuring solar noon from one day to another. This is why solar noon changes about 30 seconds every day around the solstice. This difference between clock time and solar time causes the northern hemisphere to have the earliest sunset a few weeks before the solstice and the latest sunrise a few weeks after. Check out this video by minutephysics for more: https://youtu.be/nZMMuv0Ltyo?si=vy0X3J9QZzaw_o13