This paper demonstrates the need for temperature awareness in sizing accelerators to target multi-DNN workloads. To that end, we build TESA, a TEmperature-aware methodology that Sizes and places Accelerators to balance both the cost and power of a multi-chip module (MCM), including DRAM power for multi-deep neural network workloads. TESA tunes the accelerator chiplet size and inter-chiplet spacing to generate a temperature-aware MCM layout, subject to user-defined latency, area, power, and thermal constraints. Using TESA for both 2D and 3D systolic array-based chiplets, we demonstrate up to 44% MCM cost savings and 63% DRAM power savings, respectively, over a temperature-unaware baseline at iso-frequency and iso-interposer area. We also demonstrate a need for TESA to obtain feasible MCM configurations for multi-DNN workloads such as augmented/virtual reality (AR/VR).