We have investigated positronium‒xenon collisions at energies below 100 meV to find a strong temperature dependences of the annihilation rates. A partial wave analysis based on a modified effective range theory (MERT) is tested to explain the temperature dependences and to find significant contributions of the p-wave scattering component. The fact that MERT works well for analyzing positronium‒xenon collisions indicates that positronium is polarized during the collisions as proposed by other theoretical and experimental researchers.