AmbiguousTimeError: Cannot infer dst time from Timestamp('2015-11-01 01:00:03'), try using the 'ambiguous' argument

[adamschultz]

In Pandas 0.19.0, there seems to be an error when setting the timezone for times close to the dst cutoff.

This issue appears very similar to #11619 and #11626, both of which have been closed. The traceback is below.

df['Timestamp'] = df['Timestamp Date'] + " " + df['Timestamp Time']
df['Timestamp'] = pd.to_datetime(df['Timestamp']).dt.tz_localize('US/Central')

---------------------------------------------------------------------------
AmbiguousTimeError                        Traceback (most recent call last)
 in ()
----> 1 df['Timestamp'] = pd.to_datetime(df['Timestamp']).dt.tz_localize('US/Central')

/Users/adam/anaconda/lib/python2.7/site-packages/pandas/core/base.pyc in f(self, *args, **kwargs)
    208 
    209             def f(self, *args, **kwargs):
--> 210                 return self._delegate_method(name, *args, **kwargs)
    211 
    212             f.__name__ = name

/Users/adam/anaconda/lib/python2.7/site-packages/pandas/tseries/common.pyc in _delegate_method(self, name, *args, **kwargs)
    130 
    131         method = getattr(self.values, name)
--> 132         result = method(*args, **kwargs)
    133 
    134         if not is_list_like(result):

/Users/adam/anaconda/lib/python2.7/site-packages/pandas/util/decorators.pyc in wrapper(*args, **kwargs)
     89                 else:
     90                     kwargs[new_arg_name] = new_arg_value
---> 91             return func(*args, **kwargs)
     92         return wrapper
     93     return _deprecate_kwarg

/Users/adam/anaconda/lib/python2.7/site-packages/pandas/tseries/index.pyc in tz_localize(self, tz, ambiguous, errors)
   1823             new_dates = tslib.tz_localize_to_utc(self.asi8, tz,
   1824                                                  ambiguous=ambiguous,
-> 1825                                                  errors=errors)
   1826         new_dates = new_dates.view(_NS_DTYPE)
   1827         return self._shallow_copy(new_dates, tz=tz)

pandas/tslib.pyx in pandas.tslib.tz_localize_to_utc (pandas/tslib.c:70327)()

AmbiguousTimeError: Cannot infer dst time from Timestamp('2015-11-01 01:00:03'), try using the 'ambiguous' argument

Here is some relevant information on the data frame.

df[['Timestamp Date', 'Timestamp Time', 'Timestamp']].head()
  Timestamp Date Timestamp Time               Timestamp
0     01-04-2016    07:10:03 AM  01-04-2016 07:10:03 AM
1     01-04-2016    07:20:04 AM  01-04-2016 07:20:04 AM
2     01-04-2016    07:30:03 AM  01-04-2016 07:30:03 AM
3     01-04-2016    07:40:03 AM  01-04-2016 07:40:03 AM
4     01-04-2016    07:50:03 AM  01-04-2016 07:50:03 AM

df.info()
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 286834 entries, 0 to 286833
Timestamp Date       286834 non-null object
Timestamp Time       286834 non-null object
Timestamp            286834 non-null object

I also had this same issue in Pandas 0.18.0 before upgrading to 0.19.0.

[jreback]

can you show a copy-pastable example. e.g. construct a frame exactly like what you need. Then apply operations to show an error.

[jreback]

In [25]: Timestamp('2015-11-01 01:00:03').tz_localize('US/Central',ambiguous=False)
Out[25]: Timestamp('2015-11-01 01:00:03-0600', tz='US/Central')

In [26]: Timestamp('2015-11-01 01:00:03').tz_localize('US/Central',ambiguous=True)
Out[26]: Timestamp('2015-11-01 01:00:03-0500', tz='US/Central')

[jreback]

In [45]: pd.to_datetime(df.iloc[:,1] + ' ' + df.iloc[:, 2])
Out[45]: 
0   2016-01-04 07:10:03
1   2016-01-04 07:20:04
2   2016-01-04 07:30:03
3   2016-01-04 07:40:03
4   2016-01-04 07:50:03
dtype: datetime64[ns]

In [46]: pd.to_datetime(df.iloc[:,1] + ' ' + df.iloc[:, 2]).dt.tz_localize('US/Central')
Out[46]: 
0   2016-01-04 07:10:03-06:00
1   2016-01-04 07:20:04-06:00
2   2016-01-04 07:30:03-06:00
3   2016-01-04 07:40:03-06:00
4   2016-01-04 07:50:03-06:00
dtype: datetime64[ns, US/Central]

[adamschultz]

Thanks for the quick reply. Here's the traceback from a minimal, reproducible example with a one-row data frame.

import pandas as pd

df2 = pd.DataFrame({'Timestamp Date': '11-01-2015', 
                   'Timestamp Time': '01:00:03'}, 
                    index=range(1))
df2['Timestamp'] = df2['Timestamp Date'] + " " + df2['Timestamp Time']
df2['Timestamp'] = pd.to_datetime(df2['Timestamp']).dt.tz_localize('US/Central')

---------------------------------------------------------------------------
AmbiguousTimeError                        Traceback (most recent call last)
 in ()
      5 df2.head()
      6 df2['Timestamp'] = df2['Timestamp Date'] + " " + df2['Timestamp Time']
----> 7 df2['Timestamp'] = pd.to_datetime(df2['Timestamp']).dt.tz_localize('US/Central')

/Users/adam/anaconda/lib/python2.7/site-packages/pandas/core/base.pyc in f(self, *args, **kwargs)
    208 
    209             def f(self, *args, **kwargs):
--> 210                 return self._delegate_method(name, *args, **kwargs)
    211 
    212             f.__name__ = name

/Users/adam/anaconda/lib/python2.7/site-packages/pandas/tseries/common.pyc in _delegate_method(self, name, *args, **kwargs)
    130 
    131         method = getattr(self.values, name)
--> 132         result = method(*args, **kwargs)
    133 
    134         if not is_list_like(result):

/Users/adam/anaconda/lib/python2.7/site-packages/pandas/util/decorators.pyc in wrapper(*args, **kwargs)
     89                 else:
     90                     kwargs[new_arg_name] = new_arg_value
---> 91             return func(*args, **kwargs)
     92         return wrapper
     93     return _deprecate_kwarg

/Users/adam/anaconda/lib/python2.7/site-packages/pandas/tseries/index.pyc in tz_localize(self, tz, ambiguous, errors)
   1823             new_dates = tslib.tz_localize_to_utc(self.asi8, tz,
   1824                                                  ambiguous=ambiguous,
-> 1825                                                  errors=errors)
   1826         new_dates = new_dates.view(_NS_DTYPE)
   1827         return self._shallow_copy(new_dates, tz=tz)

pandas/tslib.pyx in pandas.tslib.tz_localize_to_utc (pandas/tslib.c:70327)()

AmbiguousTimeError: Cannot infer dst time from Timestamp('2015-11-01 01:00:03'), try using the 'ambiguous' argument

[jreback]

@adamschultz ok fixed in #14405 ; this was a bug in interpreting a passed boolean. Note that you still MUST pass the ambiguous argument, as this fundamentally IS an ambiguous time.