To change the linewidth of a hatch in matplotlib, we can set the linewidth of the hatch in the params.
import numpy as np from matplotlib import pyplot as plt plt.rcParams["figure.figsize"] = [7.50, 3.50] plt.rcParams["figure.autolayout"] = True x = np.linspace(-5, 5, 25) y = np.sin(x) plt.rcParams['hatch.linewidth'] = 1 plt.scatter(x, y, s=700, marker='s', linewidth=0.05, facecolor='red', hatch='/', alpha=.7) plt.show()