script.py

import sqlalchemy
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker

import datetime

Base = declarative_base()

engine = create_engine('postgresql://postgres:@localhost/testing')
session = sessionmaker(bind=engine)()

class Test(Base):
    __tablename__ = 'testing'

    id = sqlalchemy.Column(sqlalchemy.Integer, primary_key=True)
    dt = sqlalchemy.Column(sqlalchemy.DateTime(timezone=True))
    dt2 = sqlalchemy.Column(sqlalchemy.DateTime())

Base.metadata.create_all(engine)

session.add(Test(dt=datetime.datetime.now(), dt2=datetime.datetime.utcnow()))
session.commit()
session.flush()

import pandas as pd
df = pd.read_sql_table('testing', engine)

script.py output

IPython 1.0.0 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: df
Out[1]:
   id                                dt                        dt2
0   1  2014-05-23 15:43:12.731037-07:00 2014-05-23 22:43:12.731046

In [2]: df['dt']
Out[2]:
0    2014-05-23 15:43:12.731037-07:00
Name: dt, dtype: object

In [3]: df['dt'][0]
Out[3]: Timestamp('2014-05-23 15:43:12.731037-0700', tz='psycopg2.tz.FixedOffsetTimezone(offset=-420, name=None)')

# Datetime with time zone field remains a tz-aware timestamp

In [4]: df['dt2']
Out[5]:
0   2014-05-23 22:43:12.731046
Name: dt2, dtype: datetime64[ns]

# Datetime without time zone is parsed into datetime64[ns]