Spin-ice compounds enable the exploration of the dynamics of magnetic monopoles in condensed matter systems. In this study, we use AC calorimetry to probe the dynamic heat capacity response of the classical spin-ice compound Dy2Ti2O7 at low temperatures (0.5–5 K). Using frequencies of 0.01–500 Hz, we observe a strong frequency dependence in the measured heat capacity, allowing us to study thermal-relaxation effects on the corresponding timescales. The relaxation time τ is determined from the frequency dependence of the heat capacity as the characteristic frequency below which the heat capacity saturates. Specific heat shows a maximum around 1 K. The extracted τ shows divergent behavior below this temperature, reaching ∼6 s at 0.65 K, similar to the relaxation time seen in previous studies. Performing dynamic Monte Carlo simulations, we verify that the specific heat frequency response has its origin in the slow magnetic monopole dynamics indigenous to spin ice. We find a timescale of 20 ms per Monte Carlo step at 4 K, in contrast to 2.5 ms mentioned in previous studies by other techniques.