South Yorkshire Fire and Rescue said the declaration was made due to the increasing demand on services due to blazes fires across the county.
In Sheffield, one fire engine was deployed to tackle a fire involving allotments on Moss Way and nearby residents were urged to keep their windows and doors closed.
But neighbouring Doncaster saw a number of wildfires in a short space of time as temperatures peaked at 40C in the afternoon – triggering a deployment of crews to douse the flames.
Firefighters were sent to grassland blazes at Rossington and Hatfield, while fires are reported to have broken out in Cusworth and Cantley too.
Meanwhile, Sprotbrough Road was shut after a wildfire broke out on a railway line, with residents describing ashes 'falling from the sky'.
Incredible aerial footage of the fire was also caught on camera as residents were told to stay away from the area or not travel to Doncaster at all if possible.
In Rotherham, the fields of Laughton-en-le-Morthen caught fire, producing thick, black smoke plumes that could be seen for miles.
Large fires were also reported between Dinnington and near Lambrell Avenue in Kiveton, and motorists were warned that the road in the area was no longer passable.
Fire crews and South Yorkshire Police were also deployed to tackle a blaze on Burton Road, in the Monk Bretton area of Barnsley.
And on a day of such huge demand for police officers and fire crews, small act of kindness by local residents have been praised.
South Yorkshire police said whilst at the scene of a blaze in Barnsley for several hours, officers were stopped by a number of members of the public who kindly offered them bottles of water, ice lollies and other cooling refreshments.
The force said: “Thank you to all those who have checked in our officers today - it is hugely appreciated.”