Original: At 100 C (373.65 K, 212 F) saturated sodium chloride brine is 39.12% salt by weight i.e. 39.12 g salt dissolves in 100mls of water at 100 C/O. At 0 C (273.15 K, 32 F) brine can only hold 35.70% salt.
Simplified: At 0, it can hold 23.3% salt.