Ease into the morning with a late breakfast at Flurys on Park Street, then take a relaxed stroll through Maidan and along Red Road to soak up the city's open spaces and weekday energy. Since it's already late morning, this is a good time to keep things light before the day warms up, perhaps ending with a short coffee stop near Kolkata Maidan or a browse through nearby bookstores and cafés.
Head into the afternoon with a slow heritage-and-lunch loop in central Kolkata, starting at Indian Coffee House for a classic meal before wandering through the stately surroundings of Dalhousie Square and the grand facades of Writer's Building and General Post Office. If you want to keep the pace unhurried, finish with a shaded detour to St. John's Church and nearby lanes for old-world architecture, then pause for an ice cream or tea as the day begins to soften.
As the heat eases, drift toward Prinsep Ghat for a breezy riverside walk and views of the Hooghly River, then linger for a calm boat ride or sunset photos along the promenade. If you'd like to round out the day with a low-key dinner, head to the Ballygunge or Golpark area for a relaxed Bengali meal, finishing with sweets from a classic local shop before calling it a day.