title: Why do I get 'Cannot infer dst time from '2017-10-29 02:04:15', try using the 'ambiguous' argument?
body: <p>I managed to create a minimal example that shows the same behaviour:</p>
  
  <pre><code>&gt;&gt;&gt; import pandas as pd
  &gt;&gt;&gt; df = pd.DataFrame({'id': [1], 'date': ['2017-10-29 02:04:15']})
  &gt;&gt;&gt; df['date'] = pd.to_datetime(df['date'])
  &gt;&gt;&gt; df['date'].dt.tz_localize('Europe/Berlin')
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/home/math/.local/lib/python3.5/site-packages/pandas/core/accessor.py", line 88, in f
      return self._delegate_method(name, *args, **kwargs)
    File "/home/math/.local/lib/python3.5/site-packages/pandas/core/indexes/accessors.py", line 99, in _delegate_method
      result = method(*args, **kwargs)
    File "/home/math/.local/lib/python3.5/site-packages/pandas/core/indexes/datetimes.py", line 2368, in tz_localize
      errors=errors)
    File "pandas/_libs/tslibs/conversion.pyx", line 977, in pandas._libs.tslibs.conversion.tz_localize_to_utc
  pytz.exceptions.AmbiguousTimeError: Cannot infer dst time from '2017-10-29 02:04:15', try using the 'ambiguous' argument
  </code></pre>
  
  <p>Why does this error occur?</p>
  
  <p>The <a href="https://pandas.pydata.org/pandas-docs/stable/generated/pandas.Series.tz_localize.html" rel="noreferrer">documentation of <code>tz_localize</code></a> doesn't explain this properly.</p>