With the continuing scaling of CMOS technologies, process variation is becoming a key factor highly impacting system-level power and temperature. Traditional methods of assuming a uniform temperature and no process variation can lead to gross inaccuracies even for system-level design, thus it is critical to consider the effects of process variation and temperature variation during early design exploration. In this paper, we describe the implementation of an architecture-level early-stage design space exploration tool that incorporates the effect of process and temperature variation for Network-on-chips(NoC). The tool is used to study the impact of process and temperature variations on power and energy-delay-product-per-flit metrics for different NoC architectures, and our simulation results show that design choices are influenced by the effects of process and temperature variation, thus demonstrating the importance of considering, and enabling the high-level impact analysis of process and temperature variation early in the design flow.