A series of fracture simulations are performed and presented. A two dimensional configuration with a notch is assembled via the popular Lennard-Jones (LJ) potential, and the configuration is subjected to displacement controlled tension tests. Five sets of analyses are performed at different temperatures, where the specimens share the same initial geometry and particle number and strain rate is fixed at the same value. Results show qualitatively that a heightened temperature may induce retardation of crack propagation, and consequently an increase in material toughness. Peak stress response is shown to increase with ambient temperature, and the trend coincides with what is commonly observed in actual toughness tests. What is also shown is local heating around crack tips. The local temperature variance is observed to concentrate behind the crack tip, i.e., deferred heat transfer. The localized heating appears more pronounced in the lower ambient temperature cases, while the effect becomes less susceptible in the higher ambient temperature cases. The phenomenon may be related to higher mobile states of particles induced by increased internal energy.