When is noon, really?
दोपहर
India runs on one timezone — IST, pegged to 82.5°E. But the country spans 29 degrees of longitude, so the sun reaches its highest point almost 104 minutes earlier in Dibrugarh than in Dwarka. Every clock reads 12:00 at the same instant. The sun doesn't.
How Earth's rotation creates the gap
Earth rotates 360° in 24 hours — that's 1° every 4 minutes. India spans 26° from Dibrugarh to Dwarka. The sun takes 104 minutes to sweep across that arc.
When the sun peaks over Dibrugarh, residents in Dwarka still have 104 minutes to wait — but every clock in India reads the same time.
Solar noon across India
The golden band sweeps east to west — the direction noon travels across the country. Cities are coloured from amber (noon comes early) to cyan (noon comes late).
The gradient: longitude vs solar noon
The relationship is perfectly linear — 4 minutes per degree of longitude. The insight isn't complicated physics; it's that India is too wide for one timezone. The dashed line marks the IST meridian at 82.5°E.
Equation of time
Earth's tilt and elliptical orbit cause solar noon to drift up to 16 minutes from the clock. This annual wobble shifts every city's solar noon in lockstep — the gradient's slope stays the same, but the whole line moves up or down with the seasons.
The full solar day — sunrise to sunset
The noon gap is just the headline. Sunrise, sunset, and day length all vary across India — driven by longitude and latitude. Northern cities get longer summer days; eastern cities see the sun first.
Each bar spans sunrise to sunset. The tick marks solar noon. Bars shift left (east, earlier) to right (west, later) — but they also change width: northern cities like Srinagar get 14h43m of daylight while southern Kochi gets 13h33m — latitude stretches the day.