Depending how warm it gets I would think it would take at least a year or more for the sap to completely harden.
I find a lot of that dried sap when I am out and about, I mostly find it under the ''Limber Pine'' trees. Some of it is hard but most of it is still somewhat soft. I have collected some of the soft sap and have heated it up and mixed it with candle wax and made some candles. With the pine scent mixed in with the wax it really does emit a rather nice pine scent.