Warning
#### Code with problem

```python


# Create columns of seasons for pair plotting colors
seasons = []

for month in features['month']:
    if month in [1, 2, 12]:
        seasons.append('winter')
    elif month in [3, 4, 5]:
        seasons.append('spring')
    elif month in [6, 7, 8]:
        seasons.append('summer')
    elif month in [9, 10, 11]:
        seasons.append('fall')

# Will only use six variables for plotting pairs
reduced_features = features[['temp_1', 'prcp_1', 'average', 'actual']]
reduced_features['season'] = seasons

```
#### Problem description
This generates the following warning message:

  **C:\PythonTestCode\MLRandomForest_Test_01.py:179: SettingWithCopyWarning: 
  A value is trying to be set on a copy of a slice from a DataFrame.
  Try using .loc[row_indexer,col_indexer] = value instead**

  **See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable    [/indexing.html#indexing-view-versus-copy](url)
  reduced_features['season'] = seasons**

Note  `reduced_features['season'] = seasons` is the code at line 179. I went to the link suggested and was unable to determine how to change my code to eliminate this warning. What can I change in the above code to eleminate this warning?  

#### Output of ``pd.show_versions()``

<details>

INSTALLED VERSIONS
------------------
commit: None
python: 3.6.2.final.0
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 94 Stepping 3, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None

pandas: 0.22.0
pytest: None
pip: 9.0.1
setuptools: 38.4.0
Cython: None
numpy: 1.14.0
scipy: 1.0.0
pyarrow: None
xarray: None
IPython: 6.2.1
sphinx: None
patsy: None
dateutil: 2.6.1
pytz: 2017.3
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: 2.0.2
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: None
html5lib: 1.0.1
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: 2.10
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None

</details>
