title: Problem with start date and scheduled date in Apache Airflow
body: <p>I am working with <a href="https://en.wikipedia.org/wiki/Apache_Airflow" rel="nofollow noreferrer">Apache Airflow</a> and I have a problem with the scheduled day and the starting day.</p>
  <p>I want a <a href="https://airflow.apache.org/docs/apache-airflow/stable/concepts/dags.html" rel="nofollow noreferrer">DAG</a> to run every day at 8:00 AM UTC. So, I did:</p>
  <pre class="lang-py prettyprint-override"><code>default_args = {
          'owner': 'airflow',
          'depends_on_past': False,
          'start_date': datetime(2020, 12, 7, 10, 0,0),
          'email': ['example@emaiil.com'],
          'email_on_failure': True,
          'email_on_retry': False,
          'retries': 1,
          'retry_delay': timedelta(hours=5)
      }
  # Never run
  dag = DAG(dag_id='id', default_args=default_args, schedule_interval='0 8 * * *',catchup=True)
  </code></pre>
  <p>The day I upload the DAG was 2020-12-07 and I wanted to run it on 2020-12-08 at 08:00:00.</p>
  <p>I set the start_date at 2020-12-07 at 10:00:00 to avoid running it at 2020-12-07 at 08:00:00 and only trigger it the next day, but it didn't work.</p>
  <p>Then I modified the starting day:</p>
  <pre class="lang-py prettyprint-override"><code>default_args = {
          'owner': 'airflow',
          'depends_on_past': False,
          'start_date': datetime(2020, 12, 7, 7, 59,0),
          'email': ['example@emaiil.com'],
          'email_on_failure': True,
          'email_on_retry': False,
          'retries': 1,
          'retry_delay': timedelta(hours=5)
      }
  # Never run
  dag = DAG(dag_id='etl-ca-cpke-spark_dev_databricks', default_args=default_args, schedule_interval='0 8 * * *',catchup=True)
  </code></pre>
  <p>Now the start date is 1 minute before the DAG should run, and indeed, because the catchup is set to True, the DAG has been triggered for 2020-12-07 at 08:00:00, but it has not being triggered for 2020-12-08 at 08:00:00.</p>
  <p>Why?</p>