Temperature Ranges and Terminology for Salts

Salts dissolve in water and lower the freezing temperature, so snow and ice cannot form. Different salts are effective at different temperatures and the amount needed varies greatly. For more information on the different salts, visit “Materials to Treat Snow and Ice.”

Terms Used to Describe Salt Temperatures

Below are the two most important phrases used to describe temperature ranges:

  • “Lowest Practical Melting Temperature” or “Lowest Effective Temperature”
    1. The temperature that a salt will melt ice in a reasonable amount of time. The melting rate slows down tremendously below this temperature until the “Eutectic Temperature” is met.
    2. Note: Different manufacturers and organizations may list different temperatures for the same salt.
  • “Eutectic Temperature”
    1. The lowest temperature that a salt can melt ice.

To help explain the concept of a “Lowest Practical Melting Temperature” or “Lowest Effective Temperature” the graph on the right shows how the melting speed and capacity (or the amount of ice the salt can melt) reach a point where the salt will not be very “effective.”  We put “effective” in quotation marks because that is a judgement call. For most homeowners rock salt may still be effective at 15 F.

Temperature Ranges for Salts

Below is a table with temperature ranges for some of the more common salts:

Type of Salt


Lowest Practical Melting Temperature

Eutectic Temperature

Salts that contain chloride

NaCl (sodium chloride) also called “rock salt”1

15 F

-6 F

MgCl2 (Magnesium Chloride)1

-10 F

-28 F

CaCl2 (Calcium Chloride)1

-20 F

-60 F

KCl (Potassium Chloride)2

25 F

13 F

Salts that do not contain chloride

CMA (Calcium Magnesium Acetate)1

20 F

-18 F

KAc (Potassium Acetate)1

-15 F

-76 F

1Source: https://stormwater.pca.state.mn.us/index.php?title=Lowest_practical_melting_temperature
2Source: http://www.dot.state.oh.us/Divisions/Operations/Maintenance/SnowandIce/Snow%20and%20Ice%20Best%20Practices/Liquid%20Chemicials%20Presentation.ppt