Temperatures hit nearly 30C in the town on Tuesday and Wednesday.
With autumn and winter on the way, it is likely be the last warmth for several months now.
Take a look at these pictures by our photographer Brian Eyre, who was out and about in Chesterfield on Wednesday.
1. SOAKING UP SEPTEMBER RAYS
David Sowden with grandson Rupert Sowden in Chesterfield's Queen's Park. Photo: Brian Eyre
2. SOAKING UP SEPTEMBER RAYS
11-month-old Aiden O'Neill. Photo: Brian Eyre
3. SOAKING UP SEPTEMBER RAYS
Baby Logan Shaw. Photo: Brian Eyre
4. SOAKING UP SEPTEMBER RAYS
Steve and Sonia Kirkland with a drink outside Chesterfield's Junction bar on Chatsworth Road. Photo: Brian Eyre