Looking at details of water steam (Steam), it shows
Specific Heat Capacity: 4.179 (J/g)/K
It should be (≈) 2.08 J/(g·K)
BTW, Wikipedia states water heat capacity as ≈ 4.184 J/(g·K), other sources give 4.181 or 4.187, is there a specific reason to choose 4.179 in the game?
Check steam properties in-game