Heat is produced at the surface of the Earth by sunlight (shortwave electromagnetic radiation) that is converted to heat energy (long-wave radiation). The distance between the Earth and the sun has little effect on heat production at the surface of the Earth. 

Instead, heat production is due to the following: 

1. Angle of the sun’s rays 
2. Length of exposure (number of daylight hours) to sunlight 
3. Albedo (reflectivity)