Why is the Northern Hemisphere generally colder during January?

Concept overview / definitionSeasons are primarily caused by Earth’s axial tilt. As Earth revolves around the Sun, the tilt changes the angle and duration of sunlight received by each hemisphere, producing seasonal temperature differences.

Why the correct option is correctIn January, the Northern Hemisphere is tilted away from the Sun. Sun rays strike it at a lower angle and days are shorter in many regions, so the total incoming solar energy is reduced, leading to colder conditions compared to the opposite hemisphere.

Why the other options are incorrectDistance from the Sun is not the main cause of seasons because Earth’s orbit is nearly circular and affects both hemispheres similarly at the same time. Rotation causes day and night, not seasonal shifts. Ocean currents can modify regional climate but cannot explain the global hemispheric season pattern.

UPSC exam tip / common confusionA common trap is “winter because Earth is farther from the Sun.” Keep it straight: axial tilt controls sun angle and day length, which control seasons. Orbit distance plays a minor role and does not alternate between hemispheres.