The rapid deployment of phasor measurements units (PMUs) supporting Wide Area Measurement System (WAMS) in smart grid has opened opportunities to enhance the grid operations through the introduction of WAMS applications. However, the increased deployment of synchrophasor technologies increases the effective attack surface available to attackers and exposesWAMS applications. Such applications have strict and stringent delay requirements, e.g., end to end delay as well as delay variation between measurements from different PMUs. In this paper, we present a mathematical model for constructing forwarding trees for PMUs’ measurements which satisfy the end-to-end delay as well as the delay variation under delay attacks. We illustrate that simple shortest path routing will result in larger fraction of data drop and that our method will achieve better delivery rate. We also validate our method against delay attacks affecting certain links in the network.