Earlier quoted context omitted.
Even if it hadn't been for Enigma, and even if it hadn't been for the weather in Russia, I still don't think it's possible to construct a sensible scenario where the eventual outcome of the war is delayed by more than a few months. If VE day didn't come in May thanks to Turing, it would have come in August thanks to Oppenheimer.
Depends on which kind of facts you are prepared to alter. E.g. you could construct scenarios where Germany and the Soviet Union would not attack each other. Or where the U.S. would not enter the war.
No offence to Turing et al, of course -- they still saved gazillions of lives.