the latest Pandas gives warning about append being depreciated.
FutureWarning: The frame.append method is deprecated and will be removed from pandas in a future version. Use pandas.concat instead.
The main difference is that concat expects an iterable list.
monnth_df = pd.concat( [ month_df,obs1 ], ignore_index=True) # month_df = month_df.append(obs1, ignore_index=True)