Incompressible flow around a pair of circular cylinders in staggered arrangements with heated upstream cylinder is investigated in this study. Three dimensional direct numerical simulation (DNS) is performed based on the spectral/hp element method with the Reynolds numbers, Re, of 500 and the Prandtl number, Pr, of 0.71. The longitudinal separation (L) to diameter (D) ratio (L/D) and transverse separation (T) to diameter (D) ratio (T/D) are varied from 2.5 to 5 and from 0.5 to 1, respectively. The first investigation focuses on the effects of cylinders placement on both flow structures and local heat transfer characteristics of both cylinders. Later, the identification of major spatially distributed features is done by extracting the proper orthogonal decomposition (POD) modes from ensemble of simulation solutions. The correlation between flow, heat transfer characteristics and POD modes is studied.