how critical are temperature and humidity when installing laminate floors?
Their install guide says 


  "Under normal conditions, Harmonics® flooring requires no acclimation
  period. Normal conditions are defined as a difference of no more than
  25°F and 20% relative humidity between the stocking/transportation
  environment of the flooring and the final installation environment of
  the flooring. Outside of normal conditions, let the planks acclimate
  for 48 hours in the unopened packaging at the normal room temperature
  in the middle of the room where the floor is to be installed.Allow air
  space between packages"


So looks like you can get installing right away.