title: Fill NaN in pandas dataframe with interpolate function
body: <p>I find a row contains two missing data from my dataframe. </p>
  
  <pre><code>data
  WeatherHR0     6.4
  WeatherHR1       6
  WeatherHR2     5.8
  WeatherHR3     5.4
  WeatherHR4     NaN
  WeatherHR5     NaN
  WeatherHR6     4.7
  WeatherHR7     4.7
  WeatherHR8     4.7
  WeatherHR9     3.8
  WeatherHR10      3
  WeatherHR11      3
  WeatherHR12    2.6
  WeatherHR13    2.2
  WeatherHR14    2.2
  WeatherHR15    2.4
  WeatherHR16    2.5
  WeatherHR17    2.4
  WeatherHR18    2.3
  WeatherHR19    2.4
  WeatherHR20    2.6
  WeatherHR21    2.3
  WeatherHR22      2
  WeatherHR23    1.8
  Name: 2008-04-12 00:00:00, dtype: object
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/d9a8L.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/d9a8L.png" alt="enter image description here"></a></p>
  
  <p>I tried to interpolate the missing values with pandas' interpolate() function. But it didn't work. I couldn't figure out why. Can someone explain the reason?</p>