Evening sun is not as hot as the mid day sun. What is the reason?

The intensity of solar radiation received at the Earth's surface depends significantly on the angle of inclination of the sun's rays. During midday, the sun is directly overhead, and its rays travel the shortest distance through the atmosphere. In contrast, during the evening, the sun is at a slant angle near the horizon. This lower solar angle forces the radiation to travel a much larger distance through the atmosphere before reaching the surface [t5]. As the path length increases, more solar energy is lost due to scattering by air molecules and fine particles, a process known as Rayleigh scattering [c4][t9]. Additionally, atmospheric gases like ozone and water vapor absorb a portion of the incoming radiation [c1][t7]. Consequently, the increased atmospheric path in the evening leads to greater attenuation of solar energy, making the evening sun feel less hot than the midday sun.

Sources

1. [1] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 8: Solar Radiation, Heat Balance and Temperature > Variability of Insolation at the Surface of the Earth > p. 67
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 19: The Motions of The Earth and Their Effects > Days Are Always Longer Than Nights at The Equator > p. 255
3. [3] Science , class X (NCERT 2025 ed.) > Chapter 10: The Human Eye and the Colourful World > 10.6.2 Why is the colour of the clear Sky Blue? > p. 169
4. [4] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 8: Solar Radiation, Heat Balance and Temperature > The Passage of Solar Radiation through the Atmosphere > p. 68