What Temperature Does Saltwater Freeze?

Quick Answer: 28 degrees +/-

Unfortunately, this is a question we may be experiencing in the next few days.  I just saw in the local news that the low temperature for Friday night is supposed to be 15 degrees!  In Charleston, SC!  The wind is going to be out of the North at 15-20 which will put the wind chill around 10.  Friday is forecast to have 16 hours below freezing.  Tomorrow and Saturday don’t look much better, either.  Luckily for us, the low tides are going to be first thing in the morning, right in the coldest part of the day. 

So, back to the question, “what temperature does saltwater freeze?”.  Well, it actually depends on the salinity of the water.  The more salty, the colder it has to be.  Generally speaking, though, the water in this part of the Atlantic freezes at 28 degrees F (or -2 degrees C).  This only becomes an issue for us oystering in South Carolina once or twice a year, if at all.  With wind chills at 10 when the tide goes out and the oysters become exposed, the water around them will freeze.  This essentially freezes the oysters into the mud.  Imagine trying to pick rocks with razor blades attached to them out of frozen mud.  Sounds like fun, right?

This can have a definite impact on shrimping as well.  Right now the water temperature in the Charleston Harbor is 53 degrees.  With a North wind and temperatures well into the teens and twentys for the next few days, the water temp will drop quickly.  If it gets to 45 degrees, it will kill the shrimp in our waters.  This will not only affect the catch right now, but next season as well as the smaller white shrimp in the creeks (that will be big white shrimp in the ocean by spring) will be killed.

Jeff and I will be out the next few days, and if my fingers warm up enough to type, I’ll give a report.  Oh yeah, and Zack (in Hawaii), Setzer (in Costa), and any other friends in the tropics- you’ll get yours.