MUD Wt. or DENSITY
 
             
    S G (=g/cm3)[1] kg/m3 kg/Litre ppg Lb/ft3 Lb/BBL Lb/in3    
    0 0 0 0 0 0 0    
    0 0 0 0 0 0 0    
    0 0 0 0 0 0 0    
    0 0 0 0 0 0 0    
    0 0 0 0 0 0 0    
    0 0 0 0 0 0 0    
    0 0 0 0 0 0 0    
     
 
   
    TEMPERATURE
 
       
    Celsius Kelvin Fahrenheit Rankine   kg/m3 γ60 (=SG) oAPI60  
    0 273.15 32 491.67   835 0.835[2] 38.0  
    -273.15 0 -459.67 0   835 0.835 38  
    -17.7777778 255.3722222 0 459.67   oAPIT Fahrenheit oAPI60  
    -273.15 0 -459.67 0   40 98 36.2  
      Enter a value in any yellow cell and read the conversions across the same line,      
      or enter one (1) to see the conversion factor (N/A for Temp & API) used for each unit.      
 
 
         
       
       
       
       
       
       
       
[1]

At 40C the Specific Gravity of Water is 1.0 and equals 1.0 gram per cm3 (1000kg/m3) or 8.345ppg.

The year-round average surface temperature in Canada is 50C.  The earth's average temperature is 150C.  At this temperature the water's Specific Gravity becomes 0.99904 or 0.99904 gram per cm3 (999kg/m3) and 8.337ppg.

Then if the average mud temperature is even higher than 150C why don't we use the temperature corrected values for rig water density - 999kg/m3 and 8.337ppg?
The answer is simple: The above values are for pure water only. While the usual (fresh) rig water (not being distilled) has an average density of 1000kg/m3 or 8.345ppg.

[2]

If a SG sample was taken at a different temperature than 60oF then, enter the resulting API value below together with the temperature to be corrected to 60oF.