The response of a micromagnetic system to changes in ambient temperature or applied field is studied as a function of the overbarrier relaxation rate and of the intermediate nonequilibrium states through which the system is passing. We first derive an equation for the thermomagnetic curve and the corresponding time-dependent dc susceptibility. Next we write down an equation for the hysteresis loop and discuss its applications to calculation of the frequency and temperature-dependent coercivity. In conclusion we present a model calculation of the switching-field distribution for a system of noninteracting uniaxial particles