The .6 oz offers 2-4 degrees F of protection and transmits 80% light. The 1 oz offers 4-7 degrees F of protection and transmits 70% light. All of this is a single layer and does not calculate additional layers.

 

Rows covers are a sun run system. Therefore, when the temps are above plant tolerances, it is important to uncover them so as to allow the sun to warm the soil. The covers are like heat traps. Uncovering also allows air to flow and prevents mildew issues.