Perhaps something along these lines will give you a direction to follow:

{tMin, tMax} = MinMax[ T[[All, 3]]]

T[[All, 3]] = (T[[All, 3]] - tMin) (tMax - tMin)

ListPlot3D[T, ColorFunction -> "TemperatureMap"]
ListContourPlot[T, PlotLegends -> True]

Sir, I have tried it but not getting anything. Can you elaborate how can i proceed to non-dimensionalize the temperature.

You can specify the style of the contours but if you do, you must generate a list for all of them:

Using the example in the List ContourPlot documentation:

clist = Function[{min, max}, 
    Join[Range[min, max/2, 0.1], {{max/2, {Red, Thick}}}, 
     Range[max/2 + 0.2, max, 0.1]]] @@ {-1, 1};

I tried to use this function as the argument in Contours but there appears to be a bug so I have to make the list separately. (No need for the function form here but maybe someone can figure out how to fix this function to work with Contours->...)

ListContourPlot[
 Table[Sin[x] Sin[y], {x, -3, 3, 0.1}, {y, -3, 3, 0.1}], 
 Contours -> clist]

to get

To find the min max range for your data you can do this first:

ListContourPlot[
  Table[Sin[x] Sin[y], {x, -3, 3, 0.1}, {y, -3, 3, 0.1}], 
  Contours -> 
   Function[{min, max}, ranges = {min, max}; Range[min, max, 0.1]]];

to define ranges to get the min and max of the data for computing a list of contours.