I wouldnt advise washing the car in sides, unless you have a fair few wash mitts, as the grit in the
lower panels will spread to the higher panels on the otherside if your not careful....
Personally i clean early in the morning before the sun rises to high to heat the panels up.. as i know your car is black like mine olaf.. so its harder the black takes all the heat in... or do it at sunset... (what i mostly do it at)... when its sunset your find the car wil be wet still after you wash all the car, and the rinse cools the panels enough to apply sealant,glaze and wax....
If you do have to wash it in the sun, not advisable, make sure you keep the car rinsed down, by washing a small area, then rinse, wash and another area, rinse, but also rinse the area before that.. and so on... that way the car remains cool and doesnt evapourate the water and leave limescale water marks... otherwise rinse the car with de-ionised water, no minerals and etc in them to leave a mark... but its expensive shower water to throw on a car.. lol