Uploaded August 2026 | Updated September 2026, 5 days ago
What time is it, sounds like one of the simplest questions imaginable.
Look at your watch, phone or computer and you have the answer. But is the time displayed on your device actually the true time?
In this video, I take a look at what we really mean when we say "the time", and discover that the answer is rather more complicated than you might expect.
So what would happen if we ignored all the political boundaries and simply used the Sun to tell us the time?
That's where Solar Time comes in.
We’ll calculate the difference between your clock time and Solar Time using nothing more complicated than Google Maps and the calculator on your phone.
I don't go through all of that mathematics in the main video. Instead, I've put the explanation and calculations below for anyone who wants to take the subject further.
___________________________________
☀️ Welcome to Nerd’s Corner ☀️
In the video, I explained the basics of getting Solar Time at your location. But (there’s always a "but") due to the tilting of the Earth on its axis and the non-circular shape of its orbit, that’s not the end of the story.
To find out exactly how many minutes apparent solar time is ahead of or behind your clock today, you don't need a fancy astronomy chart.
You can calculate it yourself using a standard pocket calculator.
Just make sure your calculator is set to degree mode — the little DEG setting — before you start!
I have checked this a few times, but mistakes do happen. So if I have got any of the maths wrong, let me know!
A. Count the Days
Grab a calendar and work out which day of the year it is, starting with January 1st as day one.
For example, if you want to find the Equation of Time for November 3rd, you add up all the days in the months leading up to it. November 3rd is the 307th day of the year.
(In a leap year, ignore the extra day at the end of February to keep things simple.)
B. Find Your Orbit Angle
Because the Earth takes approximately 365 days to travel through a complete 360-degree orbit around the Sun, we need to convert your day number into an angle.
1. Take your day number (307) and subtract 81.
Scientists use 81 as a convenient reference point close to the spring equinox in March.
307 − 81 = 226
2. Divide that number by 365, the approximate number of days in a year.
226 ÷ 365 = 0.6192
3. Multiply that result by 360, the number of degrees in a circle.
0.6192 × 360 = 222.9°
And there is your magic orbit angle:
222.9 degrees
C. I’m Not Really Sure What to Call This Bit
I’ll come up with a name one day.
You’ll need your calculator for this bit, and we’re going to use the sine and cosine buttons.
They are normally shown as SIN and COS.
We use these to calculate three terms which, when combined, give us an approximation of the Equation of Time.
It’s probably simpler to do this in three sections and then add them together.
The First Piece
Take your orbit angle of 222.9° and double it:
222.9 × 2 = 445.8°
Press the SIN button on 445.8°, then multiply the result by 9.87.
This gives you approximately:
+9.8 minutes
The Second Piece
Take your original orbit angle of 222.9°.
Press the COS button on it, then multiply the result by −7.53.
This gives you approximately:
+5.5 minutes
The Third Piece
Take the same orbit angle of 222.9°.
Press the SIN button on it, then multiply the result by −1.5.
This gives you approximately:
+1.0 minute
D. Add the Three Pieces Together
Now just add those three answers together:
👉 9.8 + 5.5 + 1.0 = +16.3 minutes
The three pieces of the calculation work together to approximate the Equation of Time, which accounts for the combined effects of the Earth's axial tilt and its elliptical orbit.
So our calculation gives an Equation of Time of approximately:
+16.3 minutes on November 3rd
In other words, on this particular date, apparent solar time is about 16 minutes ahead of mean solar time.
🏆 The Grand Finale
Now all you have to do is combine your map-position difference from the video with your seasonal Equation of Time calculation to get the ultimate answer.
• Your map position at the White House says the Sun is running late: −8 minutes
• The Equation of Time is making apparent solar time run ahead: +16.3 minutes
Combine them:
👉 −8 + 16.3 = +8.3 minutes
So, roughly +8 minutes.
Even though the White House's location usually makes the Sun about 8 minutes late compared with the official time-zone meridian, the seasonal Equation of Time is so large in November that it completely overpowers that difference, swinging the final answer to about 8 minutes ahead.
This means that on November 3rd, true solar noon — the moment our alien friend sees the Sun reach its absolute highest point over the roof — happens when the watch says approximately 11:52 AM.
By the time the clock reaches 12:00 PM, true solar noon has already been and gone.
So, the next time you look at your watch to see if you are late for lunch, remember:
You are only late according to human laws.
What time is it, sounds like one of the simplest questions imaginable.
Look at your watch, phone or computer and you have the answer. But is the time displayed on your device actually the true time?
In this video, I take a look at what we really mean when we say "the time", and discover that the answer is rather more complicated than you might expect.
So what would happen if we ignored all the political boundaries and simply used the Sun to tell us the time?
That's where Solar Time comes in.
We’ll calculate the difference between your clock time and Solar Time using nothing more complicated than Google Maps and the calculator on your phone.
I don't go through all of that mathematics in the main video. Instead, I've put the explanation and calculations below for anyone who wants to take the subject further.
___________________________________
☀️ Welcome to Nerd’s Corner ☀️
In the video, I explained the basics of getting Solar Time at your location. But (there’s always a "but") due to the tilting of the Earth on its axis and the non-circular shape of its orbit, that’s not the end of the story.
To find out exactly how many minutes apparent solar time is ahead of or behind your clock today, you don't need a fancy astronomy chart.
You can calculate it yourself using a standard pocket calculator.
Just make sure your calculator is set to degree mode — the little DEG setting — before you start!
I have checked this a few times, but mistakes do happen. So if I have got any of the maths wrong, let me know!
A. Count the Days
Grab a calendar and work out which day of the year it is, starting with January 1st as day one.
For example, if you want to find the Equation of Time for November 3rd, you add up all the days in the months leading up to it. November 3rd is the 307th day of the year.
(In a leap year, ignore the extra day at the end of February to keep things simple.)
B. Find Your Orbit Angle
Because the Earth takes approximately 365 days to travel through a complete 360-degree orbit around the Sun, we need to convert your day number into an angle.
1. Take your day number (307) and subtract 81.
Scientists use 81 as a convenient reference point close to the spring equinox in March.
307 − 81 = 226
2. Divide that number by 365, the approximate number of days in a year.
226 ÷ 365 = 0.6192
3. Multiply that result by 360, the number of degrees in a circle.
0.6192 × 360 = 222.9°
And there is your magic orbit angle:
222.9 degrees
C. I’m Not Really Sure What to Call This Bit
I’ll come up with a name one day.
You’ll need your calculator for this bit, and we’re going to use the sine and cosine buttons.
They are normally shown as SIN and COS.
We use these to calculate three terms which, when combined, give us an approximation of the Equation of Time.
It’s probably simpler to do this in three sections and then add them together.
The First Piece
Take your orbit angle of 222.9° and double it:
222.9 × 2 = 445.8°
Press the SIN button on 445.8°, then multiply the result by 9.87.
This gives you approximately:
+9.8 minutes
The Second Piece
Take your original orbit angle of 222.9°.
Press the COS button on it, then multiply the result by −7.53.
This gives you approximately:
+5.5 minutes
The Third Piece
Take the same orbit angle of 222.9°.
Press the SIN button on it, then multiply the result by −1.5.
This gives you approximately:
+1.0 minute
D. Add the Three Pieces Together
Now just add those three answers together:
👉 9.8 + 5.5 + 1.0 = +16.3 minutes
The three pieces of the calculation work together to approximate the Equation of Time, which accounts for the combined effects of the Earth's axial tilt and its elliptical orbit.
So our calculation gives an Equation of Time of approximately:
+16.3 minutes on November 3rd
In other words, on this particular date, apparent solar time is about 16 minutes ahead of mean solar time.
🏆 The Grand Finale
Now all you have to do is combine your map-position difference from the video with your seasonal Equation of Time calculation to get the ultimate answer.
• Your map position at the White House says the Sun is running late: −8 minutes
• The Equation of Time is making apparent solar time run ahead: +16.3 minutes
Combine them:
👉 −8 + 16.3 = +8.3 minutes
So, roughly +8 minutes.
Even though the White House's location usually makes the Sun about 8 minutes late compared with the official time-zone meridian, the seasonal Equation of Time is so large in November that it completely overpowers that difference, swinging the final answer to about 8 minutes ahead.
This means that on November 3rd, true solar noon — the moment our alien friend sees the Sun reach its absolute highest point over the roof — happens when the watch says approximately 11:52 AM.
By the time the clock reaches 12:00 PM, true solar noon has already been and gone.
So, the next time you look at your watch to see if you are late for lunch, remember:
You are only late according to human laws.
