Proton resonance frequency (PRF) shift temperature mapping is influenced by B₀ field drift, temperature dependent electromagnetic property changes that alter phase velocity, alpha calibration and temperature dependent magnetic susceptibility changes. This work details PRF thermometry at 7.0T of a thermal MR setup. In a homogeneous agarose phantom PRF reading accuracy is within the accuracy of fiber optic sensor readings (0.29±0.21)°C. Temperature dependent magnetic susceptibility changes in pure fat lead to significant temperature reading errors. However, for more realistic thermal MR applications in the human brain (ΔT<10°C, volume fat fractions <10-20%), temperature reading accuracy is comparable to water-based samples.