A big misconception about pavers is that everyone thinks it has to be spring or summer to install them. This belief stems from to old brick and mortar methods which required temperatures to be ideal for the mortar to properly set. Even today they have additives for mortar which solves the problem. 
Since interlocking pavers required no mortar the system can be installed year round. The only concern is dealing with the frozen ground which at times can be challenging but is usually dug out anyway in order for the base materials to be installed. The winter is a slow season for the paver industry and usually you can find good deals because companies want to keep their crews busy year round. In addition, when spring does arrive you will have a jump start on the new planting & gardening season since your hardscaping will have already been installed.