In the present study, the turbulent statistics is analyzed to find physical factors showing a high correlation to the turbulent Prandtl number (Pr_t) spatially varying in a flow subject to local acceleration and deceleration. Local acceleration and deceleration in the flow are induced by a wedge geometry and the flow is predicted using direct numerical simulations (DNS). The Pr_t shows a lower value in a region under local acceleration than under local deceleration. Investigation of the turbulent budget terms of turbulent kinetic energy (TKE) and temperature variance indicates that the production term of TKE shows a high correlation to the Pr_t variation. Investigation of the convection velocities from the space-time correlation of fluctuations of velocity and temperature shows that the convection velocity of a velocity fluctuation is sharply changed, and that of a temperature one is biased and increases with respect to Pr. This is closely related to the Pr_t variation. From investigation of time-scale ratios of the dissipation terms of TKE and temperature variance, it is confirmed that a molecular diffusivity affects the Pr_t.