It gives a higher humidity for a while but the hygrometer itself gets dried out from the heat source and then says it's a lot less humid than the rest of the tank, meaning you could mist too much. With horned frogs all but the cornuta are very hardy with humidity and seem to do fine with temporary increases rather than constant high humidity, as after all they're not tropical but sub-tropical (accept from the cornuta). I don't use a hygrometer on mine, never will, just keep the substrate moist.