Editing Solar zenith angle (section)

=== Minimum and Maximum ===
[[File:Solar Zenith Angle min.png|thumb|The daily minimum of the solar zenith angle as a function of latitude and day of year for the year 2020.]]

[[File:Solar Zenith Angle max.png|thumb|The daily maximum of the solar zenith angle as a function of latitude and day of year for the year 2020.]]

At any given location on any given day, the solar zenith angle, <math>\theta_{s}</math>, reaches its minimum, <math>\theta_\text{min}</math>, at local solar noon when the hour angle <math>h = 0</math>, or <math>\lambda_{s}-\lambda_{o}=0</math>, namely, <math>\cos\theta_\text{min} = \cos(|\phi_{o}-\phi_{s}|)</math>, or <math>\theta_\text{min} = |\phi_{o}-\phi_{s}|</math>. If <math>\theta_\text{min} > 90^{\circ}</math>, it is polar night.

And at any given location on any given day, the solar zenith angle, <math>\theta_{s}</math>, reaches its maximum, <math>\theta_\text{max}</math>, at local midnight when the hour angle <math>h = -180^{\circ}</math>, or <math>\lambda_{s}-\lambda_{o}=-180^{\circ}</math>, namely, <math>\cos\theta_\text{max} = \cos(180^{\circ}-|\phi_{o}+\phi_{s}|)</math>, or <math>\theta_\text{max} = 180^{\circ}-|\phi_{o}+\phi_{s}|</math>. If <math>\theta_\text{max} < 90^{\circ}</math>, it is polar day.