How does GlassX know what season it is?

A prismatic outer layer reflects solar radiation in summer months when the sun is higher angle > 40°, reflecting solar heat gain.

In the winter months, when the sun is lower in the sky > 35°, the Prism allows more solar gain in winter or Heating Degree Days when it is most needed.

In affect the Prism gives GlassX a variable G-value or Solar-Heat-Gain-Coefficient for seasonal conditions.

Summer: Sun high in the sky > 40°
Solar-Heat-Gain-Coefficient (G-value) = 6-9%
summer How does GlassX know what season it is?
Winter: Shallow winter sun < 35° Solar-Heat-Gain-Coefficient (G-value) = 33-35% winter How does GlassX know what season it is?