Surface temperature? Saturn probably doesn't HAVE a "surface".
Black dwarfs have the lowest surface temperature.
the color of stars with the lowest surface temperature is red
the color of stars with the lowest surface temperature is red
The lowest surface temperature is Jupiter. 
Red stars have the lowest surface temperatures.
Technically speaking, Neptune is the planet with the lowest surface temperature; however, Neptune does not have a solid surface.
It has no land.
Red
-270 degrees Fahrenheit
About -185°C.
by the temperature on the planet
About 0.5-2 bar.