Home » World Geography » Physical Geography of the World » Origin and Evolution of Universe Solar System » Local and Standard Time and the International Date Line » Local Time
- The time at a particular place with reference to the overhead position of the sun in the sky is considered as the local time of that place.
- Local time of a particular place is determined by the mid-day sun. All places on the same meridian experience noon at the same time.
- As the Earth rotates 360º in 24 hours, in 1 hour it would rotate 360º/24º or 15º.
- Similarly, the earth would take 4 minutes to rotate 1º.
- Therefore, when it is midday at a particular place, the time would differ by 4 minutes for each degree of longitude east or west of that meridian.
- As the Earth rotates from west to east, places to the east see the sun first and so the time is ahead, while places to the west see the sun later and so are behind the time.
- Hence, if the time at Greenwich or 0º meridian is noon, it would be 12.04 pm at 1º E and 11.56 am at 1º W and similarly it would be11 am at 15º W and 1 pm at 15º E.
- Thus, each country has many local times and larger the E-W extent, the more the differences in local times.
