The charity was running the event at Woodlands Farm on York Road from 11am on Sunday.
-> Leeds Cat Rescue issues warning after putting down maggot infested kittensHowever, by 1pm the charity had put out a notice that the event was cancelled over fears for the safety of the animals at the event.
A spokesman said online: "The temperature is now too high for dogs to be out. Unfortunately our #FunDay is now cancelled. Please do not bring your #dogs to the centre
"Leeds Fun Day is cancelled! Thanks to all who made it along this morning & apologies for the short notice but we know you'll understand we have to put welfare of visiting dogs & supporters first.
"Unfortunately the temperature rose very quickly. Prior to this point the weather forecast was well within vet recommended level hence deciding to go ahead. We can only apologise for any inconvenience caused."