title: Why does my xlabel not show up? (It's not getting cut off)
body: <p>I'm making a plot and for some reason my xlabel is not showing up. I don't think it is getting cut off, because when I call <code>tight_layout</code> it still doesn't show up. Any idea what is causing this issue? Here is the code used to generate the figure with some made up data.</p>
  
  <pre><code>import matplotlib.pyplot as plt
  import numpy as np
  
  
  fig, ax = plt.subplots(figsize=(8,5))
  
  Months = ['May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct']
  
  P = [220, 120, 50, 24, 54, 72]
  T = [7, 12, 18, 24, 14, 5]
  
  ax.bar(np.arange(1.5, len(P)+1.5), P, 0.5, label='Precipitation', color='k');
  ax.set_ylabel("Precipitation, mm", fontsize=12)
  ax.legend(loc=2, frameon=False, fontsize=12)
  
  ax2 = ax.twinx()
  ax2.plot(np.arange(1.75, len(P)+1.75), T, label='Air Temperature');
  ax2.set_ylabel(r'Air Temperature, $^{o}$C', fontsize=12)
  ax2.legend(loc=1, frameon=False, fontsize=12)
  ax2.set_ylim(0,30)
  
  plt.xticks(np.arange(1.75, len(P)+1.75), Months)
  plt.xlim(1, 7.5)
  plt.xlabel("2013", fontsize=12)
  
  plt.tight_layout()
  </code></pre>
  
  <p>And an image of the figure itself (With the xlabel not present).</p>
  
  <p><img src="https://i.stack.imgur.com/6MqOv.png" alt="enter image description here"></p>