title: Fetching Standard Meteorological Week from pandas dataframe date column
body: <p>I have a pandas dataframe which is having long term data,</p>
  <pre><code>
          point_id     issue_date  latitude   longitude   rainfall    
  0           1.0      2020-01-01    6.5          66.50      NaN      
  1           2.0      2020-01-02    6.5          66.75      NaN       
  
  ... ... ... ... ... ... ... ...
  
  
  6373888   17414.0    2020-12-30   38.5          99.75      NaN       
  6373889   17415.0    2020-12-31   38.5          100.00     NaN  
  
  
  6373890 rows × 5 columns     
  </code></pre>
  <p>I want to extract the <a href="http://www.icar-crida.res.in:8080/naip/downloads/Standard%20Week%20Chart.pdf" rel="nofollow noreferrer">Standard Meteorological Week</a> from its issue_date  column, as
  given in this figure.</p>
  <p><a href="https://i.stack.imgur.com/IAg5G.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/IAg5G.png" alt="figure" /></a></p>
  <p>I have tried in 2 ways.</p>
  <p>1st</p>
  <pre><code>lulc_gdf['smw'] = lulc_gdf['issue_date'].astype('datetime64[ns]').dt.strftime('%V')
  </code></pre>
  <p>2nd</p>
  <pre><code>lulc_gdf['iso'] = lulc_gdf['issue_date'].astype('datetime64[ns]').dt.isocalendar().week
  </code></pre>
  <p>The output in both cases is same</p>
  <pre><code>
          point_id     issue_date  latitude   longitude   rainfall    smw   iso
  0           1.0      2020-01-01    6.5          66.50      NaN       01    1
  1           2.0      2020-01-02    6.5          66.75      NaN       01    1
  
  ... ... ... ... ... ... ... ...
  
  
  6373888   17414.0    2020-12-30   38.5          99.75      NaN       53   53
  6373889   17415.0    2020-12-31   38.5          100.00     NaN       53   53
  
  
  6373890 rows × 7 columns
  </code></pre>
  <p>The issue is that the week starts here by taking reference of Sunday or Monday as the starting day of week, irrespective of year.</p>
  <p>Like here in case of year 2020 the day on 1st January is Wednesday (not Monday),
  so the 1st week is of 5 days only i.e (Wed, Thu, Fri, Sat &amp; Sunday).</p>
  <pre><code>            year    week    day    issue_date
  0           2020      1      3     2020-01-01
  1           2020      1      4     2020-01-02
  2           2020      1      5     2020-01-03
  3           2020      1      6     2020-01-04
  ... ... ... ...
  
  6373889     2020      53     4     2020-12-31
  
  </code></pre>
  <p>But in the case of <strong>Standard Meteorological Weeks</strong>,
  I want output as:
  <strong>for every year</strong></p>
  <pre><code>1st week should always be from - 1st January to 07th January
  2nd week from -                  8th January to 14th January 
  3rd week from -                  15th January to 21st January 
  ------------------------------- and so on 
  </code></pre>
  <p>irrespective of the starting day of year (Sunday, monday etc).</p>
  <p>How to do so?</p>