title: TypeError: Invalid comparison between dtype=datetime64[ns, UTC] and datetime64
body: <p>Im trying to specifiy the timeframe in which I want to evaluate the csv data.</p>
  <p>I thought converting the date I entered to <code>datetime64</code> using <code>numpy.datetime64</code> would solve the issue, but it seems <code>datetime64[ns, UTC]</code> is another format.</p>
  <p>This is what I tried, and im getting the above error: Invalid comparison between <code>dtype=datetime64[ns, UTC]</code> and <code>datetime64</code>.</p>
  <p>How can I convert the dtype to <code>datetime64[ns UTC]</code> or the other way around?</p>
  <p>This is the code:</p>
  <pre class="lang-py prettyprint-override"><code>df = pd.read_csv('/Users/youruser/Desktop/0b13c0f751243fda1229b7601db2c51c.csv', names=headers)
  
  df['dt_iso'] = df['dt_iso'].map(lambda x: datetime.strptime(str(x), '%Y-%m-%d %H:%M:%S %z %Z'))
  
  
  start_date = numpy.datetime64('2011-05-01T01:00:00.000000+0100')
  end_date = numpy.datetime64('2012-05-01T01:00:00.000000+0100')
  mask = (df['dt_iso'] &gt; start_date) &amp; (df['dt_iso'] &lt;= end_date)
  
  x = mask['dt_iso']
  y = df['temp']
  </code></pre>
  <p>Thanks in advance!</p>
  <p>Bonus question:</p>
  <pre class="lang-py prettyprint-override"><code>df['dt_iso'] = df['dt_iso'].map(lambda x: datetime.strptime(str(x), '%Y-%m-%d %H:%M:%S %z %Z'))
  </code></pre>
  <p>What exactly does this line of code do? As far as I understand, it takes the Date information from the csv, makes a dtype object from it, then maps it to the dt_iso values. So is the unit of a datetime object <code>datetime64[ns UTC]</code>?</p>