So I got curious and looked up MIL-STD-2161C and it had this to say:
"5.1.7 Solar heat reflection. With the exception of where tactical paint schemes are employed, the upper surfaces of the fuselage of all land-based cargo, transport, and utility planes shall be painted insignia white, FED-STD-595, color number 17925. The white color shall begin at the top, forward edge of the pilot’s enclosure, extending aft to include the vertical stabilizer and elevator, and extending down each side of the fuselage to the bottom of the windows, in accordance with Appendices C and D."