正午太阳计算器
使用此正午太阳计算器快速获得准确的计算结果。
Offset from Clock Noon
-4.1 min
Offset from Clock Noon vs Your Longitude
公式
## Solar Noon Solar noon is when the Sun crosses your local meridian (highest point in the sky). It differs from clock noon because your longitude may not match your time zone's standard meridian. ### Formula **Offset = (Standard Meridian - Your Longitude) × 4 minutes** Each degree of longitude corresponds to 4 minutes of solar time (360° / 24 hours = 15°/hour). The equation of time (up to ±16 min seasonal variation) is not included here.
计算示例
New York City: longitude -73.97°, Eastern time zone meridian -75°.
- 01Offset = (-75 - (-73.97)) × 4 = -1.03 × 4 = -4.12 min
- 02Solar noon ≈ 12:00 - 4.12 min = 11:55:53
- 03The Sun is highest about 4 minutes before clock noon.
常见问题
Why isn't solar noon at 12:00?
Your location likely is not on the exact standard meridian of your time zone. Also, the equation of time causes seasonal shifts of up to 16 minutes.
What is the equation of time?
A correction for Earth's elliptical orbit and axial tilt, causing solar noon to drift up to 16 minutes early or late through the year. This calculator gives the longitude-based offset only.
Does daylight saving time affect this?
Yes. During DST, clock noon is shifted one hour later, so solar noon is roughly around 1:00 PM clock time.