According to Official Guinness Records,
The most weekdays identified from dates in one minute is 103 and was achieved by Jayasimha Ravirala (India), at Castle Venue, Visakhapatnam, India, on 2 July 2015. The dates were randomly selected between 1 January 1600 and 31 December 2100.
For a complete list of 1900 records, please visit 1900 Guinness Records in India.