direct sunlight factor
As with it's twin, wind chill factor, direct sunlight factor-- or DSF -- changes the temperature of an object when affected by it, in this case raising the temperature -- rather than lowering it -- in relation to the temperature of the air, due to the warming rays of direct, unimpeded sunshine on said object.
Despite the frigid temperatures at the airport this morning, Josh was able to get all the ice off his plane quickly by pulling it out of the hangar and into the sunshine where the direct sunlight factor raised the plane's surface temperature rapidly to melt it.