English: Spectral distribution of sunlight. Widely available charts of solar irradiance as a function of wavelength are often misinterpreted as meaning that the "peak amount" of sunlight is emitted near the center of the visible range. Yet, the observed peak is merely an artifact of one particular way of plotting the spectrum. This figure shows the solar spectrum (or a 5775 K blackbody approximation to the solar spectrum) expressed in multiple ways: as a spectral irradiance with respect to (a) wavelength, (b) fractional bandwidth (logarithm of wavelength or frequency), and (c) frequency or wavenumber. These different ways of expressing the same spectrum peak at, respectively, 502 nm, 635 nm, and 883 nm. These differing peak values show that the underlying spectrum cannot be said to have a unique place in the spectrum where it reaches its maximum. Another way of characterizing the spectrum is to consider percentiles: 10, 25, 50, 75, 90 percent of the power in the spectrum is associated with wavelengths less than 380, 502, 711, 1065, 1624 nm, respectively.

References:

Mobley, Curtis. "A Common Misconception". https://www.oceanopticsbook.info/view/light-and-radiometry/level-2/common-misconception Retrieved 6 March 2025.

Marr, Jonathan M.; Wilkin, Francis P. (2012). "A Better Presentation of Planck's Radiation Law". American Journal of Physics. 80 (5): 399. arXiv:1109.3822. Bibcode:2012AmJPh..80..399M. doi:10.1119/1.3696974. S2CID 10556556.

https://scholarship.haverford.edu/cgi/viewcontent.cgi?article=1579&context=physics_facpubs