title: Matplotlib blank space with no color when use fill_between with where option
body: <p><strong>Update:</strong></p>
  
  <p>I slice days into 100 points then interpolate the corresponding value of <code>min_temp</code> and <code>max_temp</code>, the result become better, but still some area have no color, how to modify it?</p>
  
  <pre><code>days_vals=numpy.linspace(1,10,100)
  min_interp=numpy.interp(days_vals,days,min_temp)
  max_interp=numpy.interp(days_vals,days,max_temp)
  plt.xticks(days)
  plt.plot(days_vals,min_interp,c='b',marker='o')
  plt.plot(days_vals,max_interp,c='g',marker='o')
  plt.fill_between(days_vals,min_interp,max_interp,where=[i&gt;35 for i in min_interp],
               facecolor='lightgreen',alpha=0.7,interpolate=False)
  plt.fill_between(days_vals,min_interp,max_interp,where=[i&lt;=35 for i in min_interp],
               facecolor='lightpink',alpha=0.7,interpolate=False)
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/dNeq8.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dNeq8.png" alt="enter image description here"></a></p>
  
  <p>==========================================================================</p>
  
  <p>I am using fill_between with where option to fill the color, <code>min_temp &gt; 35</code> fill green and <code>min_temp &lt;= 35</code> fill pink, but see the result is not as my expected
  there are so many blank area with no color.
  <a href="https://i.stack.imgur.com/tVq4Q.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/tVq4Q.png" alt="enter image description here"></a></p>
  
  <p>I search one question somelike my issue <a href="https://stackoverflow.com/questions/19214274/matplotlib-fill-between-edge-effect-with-where-argument">link</a></p>
  
  <p>it solution is to add additional data-points to the series that that lie on the axis, but it not fix my issue</p>
  
  <p><strong>How can i modify my codes to make the color continuous with no blank space?</strong></p>
  
  <p>here's the codes:</p>
  
  <pre><code>from matplotlib import pyplot as plt
  
  days=range(1,11)
  max_temp=[37, 35, 42, 36, 39, 56, 50, 45, 41, 39]
  min_temp=[32, 30, 37, 20, 34, 40, 37, 38, 32, 30]
  fig=plt.figure(figsize=(10,8))
  font={'weight':'normal',
        'color':'cyan',
        'fontsize':24,
        }
  plt.title('Weather 2014',fontdict=font)
  plt.xlabel('Month',fontdict=font)
  plt.ylabel('Temperature',fontdict=font)
  plt.title('Weather 2014',fontdict=font)
  plt.xlabel('Month',fontdict=font)
  plt.ylabel('Temperature',fontdict=font)
  plt.xticks(days)
  plt.plot(days,max_temp,marker='o',mfc='red',mec='None',markersize=3,label='Max Temp')
  plt.plot(days,min_temp,marker='o',mfc='g',mec='None',markersize=3,label='Min Temp')
  
  
  '''add additional data points'''
  eta=1e-6
  plt.fill_between(days,min_temp,max_temp,where=[i+eta&gt;35 for i in min_temp],
                   facecolor='lightgreen',alpha=0.7)
  plt.fill_between(days,min_temp,max_temp,where=[i-eta&lt;=35 for i in min_temp],
                   facecolor='lightpink',alpha=0.7)
  plt.legend(loc='upper left',bbox_to_anchor=(1,1))
  fig.autofmt_xdate()
  plt.grid(True)
  plt.show()
  </code></pre>