def plot_rh(self, rh, plot_range=None):
        """
        Required input:
            RH: Relative humidity (%)
        Optional Input:
            plot_range: Data range for making figure (list of (min,max,step))
        """
        # PLOT RELATIVE HUMIDITY
        if not plot_range:
            plot_range = [0, 100, 4]
        self.ax3 = fig.add_subplot(4, 1, 3, sharex=self.ax1)
        self.ax3.plot(self.dates, rh, 'g-', label='Relative Humidity')
        self.ax3.legend(loc='upper center', bbox_to_anchor=(0.5, 1.22), prop={'size': 12})
        self.ax3.grid(b=True, which='major', axis='y', color='k', linestyle='--',
                      linewidth=0.5)
        self.ax3.set_ylim(plot_range[0], plot_range[1], plot_range[2])

        self.ax3.fill_between(self.dates, rh, self.ax3.get_ylim()[0], color='g')
        self.ax3.set_ylabel('Relative Humidity\n(%)', multialignment='center')
        self.ax3.xaxis.set_major_formatter(mpl.dates.DateFormatter('%d/%H UTC'))
        axtwin = self.ax3.twinx()
        axtwin.set_ylim(plot_range[0], plot_range[1], plot_range[2])
Required input:
            RH: Relative humidity (%)
        Optional Input:
            plot_range: Data range for making figure (list of (min,max,step))