A spokesperson from Thanet District Council said on Sunday: “We were informed that an event at Dreamland was closed early due to the heat and a medical related incident.
“We await further details relating to the event.”
The festival was due to feature artists including Andy C, Wilkinson and K Motionz.
An amber heat alert is in force across most of England, meaning health services and members of the public could be affected by the heat, according to the UK Health Security Agency.
In June 2024, 17-year-old Emily Stokes died after taking MDMA at a drum and base event at the attraction.
Kent Police and Dreamland have been approached for comment.