Subplot Cartopy

import matplotlib as mpl
mpl.use('Agg')
import numpy as np
import cartopy as cart
from matplotlib import pyplot as plt
from matplotlib.colors import BoundaryNorm

def plotmaps(precip_0, precip_1, precip_2, lats, lons):

    # fix lats and lons
    deltalat = np.mean(np.diff(lats)) / 2.
    deltalon = np.mean(np.diff(lons)) / 2.
    lats = lats - deltalat
    lons = lons - deltalon

    projection = cart.crs.PlateCarree()

    fig, axs = plt.subplots(nrows=1, ncols=3, figsize=(15, 10),
                            constrained_layout=False,
                            subplot_kw={'projection': projection})

    cmap = mpl.cm.get_cmap('rainbow')

    cmap.set_over('#ED0000')

    clevs = (0., 1., 2., 3., 4., 5., 10., 15., 20.,
             25., 30., 40., 50., 60., 70., 80.)

    norm = BoundaryNorm(clevs, ncolors=cmap.N, clip=False)

    grid_limits = [-51., -27., -22., 5.]

    precips = [precip_0, precip_1, precip_2]

    axlist = axs.flatten()

    for i, axi in enumerate(axlist):

        img = axi.pcolormesh(lons, lats, precips[i], cmap=cmap,
                             norm=norm, transform=projection)

        gf = axi.gridlines(xlocs=range(-180, 181, 4),
                           ylocs=range(-90, 91, 2),
                           draw_labels=True, linewidth=0.01)

        gf.xlabels_top = False
        gf.ylabels_right = False
        gf.xformatter = cart.mpl.gridliner.LONGITUDE_FORMATTER
        gf.yformatter = cart.mpl.gridliner.LATITUDE_FORMATTER
        gf.xlabel_style = {'color': 'k', 'size': 9, 'weight': 'bold'}
        gf.ylabel_style = {'color': 'k', 'size': 9, 'weight': 'bold'}

        states = cart.feature.NaturalEarthFeature(
            category='cultural',
            scale='50m', facecolor='none',
            name='admin_1_states_provinces_shp')

        axi.add_feature(states, edgecolor='k')

        countries = cart.feature.NaturalEarthFeature(
            category='cultural',
            scale='50m', facecolor='none',
            name='admin_0_countries')

        axi.add_feature(countries, edgecolor='k')

        axi.set_extent(grid_limits, projection)

    # pos x,  pos y, size x, size y
    cb_ax = fig.add_axes([0.91, 0.302, 0.015, 0.383])

    bar = fig.colorbar(img, cax=cb_ax, extend='max',
                       shrink=0.8, pad=0.0, spacing='uniform',
                       orientation='vertical', ticks=clevs,
                       extendfrac='auto')

    bar.set_label(label=f'(mm)', size=10, weight='bold')

    # bar.tick_params(labelsize=10)  # not working

    # bar.img.set_yticklabels(clevs, fontsize=9, weight='bold')  # not working

    axi.set_title('PRECIPITATION', fontsize=9, loc='left',
                  weight='bold')

    # plt.show()

    plt.savefig('precips.png', dpi=200, bbox_inches='tight')

    plt.close()