Dave is right about drying your pt... but if you have new pt 2X6 and need to get the project done now - try LocTite PL glue. It can glue wood to cement and other surfaces. I did an in shop experiment with it and glued 2 scrap pieces of bamboo flooring together, finished side to finish side. I could not pry them apart or bang them apart with sharp blows. It's considered a construction adhesive so I would think Liquid Nails would also work. try gluing scarps together and see if it works.
Its' never hot or cold in New Hampshire... its' always seasonal.