An example speaks 1000 words.

Does anyone know when LAN Local Apparent Noon will occur today at the Prime Meridian. Answer in UTC please.


On November 1, local apparent noon will occur 16.3 minutes before actual noon on the Prime Meridian. For other dates, see

Thank you drwls this confirms my understanding.


To determine when LAN (Local Apparent Noon) will occur today at the Prime Meridian in UTC, we need to know the current date. Since you mentioned "November 1," let's use that as an example.

To calculate the Local Apparent Noon time accurately, the first step is to determine the Equation of Time for that specific date. The Equation of Time accounts for the slight variations in the Earth's orbit and axial tilt, which cause the time of solar noon to differ from clock noon.

To obtain the Equation of Time value, you can refer to websites like By inputting the current date (in this case, November 1), you'll find the Equation of Time for that day.

With the Equation of Time value, subtract it from 12:00 PM (noon) UTC to get the approximate Local Apparent Noon time on the Prime Meridian for that specific date. In the given example, you mentioned that Local Apparent Noon occurs 16.3 minutes before actual noon at the Prime Meridian. Therefore, subtracting that from 12:00 PM UTC would give you the desired time.

Remember that the Equation of Time changes throughout the year, so it's crucial to calculate it for the specific date you need. Additionally, the concept of Local Apparent Noon may be affected by factors such as daylight saving time adjustments, local time zones, and geographic location.