Design methods and systems disclosed use a process window-aware timing analysis of an integrated circuit (IC) chip design for improved accuracy. Specifically, a process distribution for the design is defined and divided into process windows. Timing parameter adjustment factors are assigned to the process windows. A timing analysis is performed in order to acquire an initial solution for a timing parameter (e.g., delay, slack or slew). For each specific process window, this initial solution is adjusted by the predetermined timing parameter adjustment factor assigned to that specific process window. The adjusted solutions for the different process windows account for process window-to-process window variations in the widths of distribution of a process parameter (e.g., leakage power) and can be used to predict whether IC chips manufactured according the IC chip design will meet established timing requirements (e.g., required arrival times (RATs)) regardless of where they fall within the process distribution.