The weather is part of the war, the Germans were not well equipped to deal with it, the Russians were, so from that perspective the Russians did in fact defeat the Germans.
The Russians were able to move their factories well out of reach of the Germans and could have continued to produce tanks, airplanes, etc...
Eventually they would have worn down the German forces for two reasons, they had more to throw at the war and Germany was fighting on multiple fronts.
“The Russians were able to move their factories well out of reach of the Germans and could have continued to produce tanks, airplanes, etc...”
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That and the USA supplied a lot of hardware.
“Now they say that the allies never helped us, but it can’t be denied that the Americans gave us so many goods without which we wouldn’t have been able to form our reserves and continue the war.”
“We didn’t have explosives, gunpowder. We didn’t have anything to charge our rifle cartridges with. The Americans really saved us with their gunpowder and explosives. And how much sheet steel they gave us! How could we have produced our tanks without American steel? But now they make it seem as if we had an abundance of all that. Without American trucks we wouldn’t have had anything to pull our artillery with.”
—Soviet General Georgy Zhukov