Go with nature (it knows best!).
Watch local shrubs/trees when they first exhibit bud swelling/breaking...

There is no set date to uncover your fig trees. Two things you want to keep in mind: First don't uncover when it's too cold. Cold damage will usually occur when temperatures below 20°F for fully dormant trees.
Secondly, don't keep it covered when it's warm. When the weather is constantly above 40°, you will run the risk of molding.
For my area I usually check the weatherin March, if I don't see very cold night in the 10 day forecast I uncover it then. March or April is the best time to uncover it.

I hope that helps.

Bass

Here is a link that might be useful: fig care

I do agree with both Person,of What they advice.
Too early and the ,plant can have frost Damage too ,late and it will get mold and many branches will die.
Personally ,I uncover,on first Day of Calendar Spring,because I am aimming to get a main crop only.
If I was aimming to get 2 crops,Breba and Main,then The date I have chosen will not work because frost will kill all Breba fruits buds.
Do not uncover your tree if you are growing a Breba fig such as Desert King,but do uncover if you are having a main crop fig type.
Hope this will HELP.
H2