@Mamapolo2016 Agreed. The "nuclear winter" that follows an all-out nuclear war will cause agricultural collapse almost everywhere. Ocean temperatures will also drop, killing algae and disrupting marine ecosystems.
Even though their nuclear arsenals have been cut in size and average yield since the end of the Cold War, a nuclear exchange between the United States and Russia would still likely initiate a much more severe nuclear winter, with much of the northern hemisphere facing below-freezing temperatures even during the summer. A global nuclear war that injected 150 Tg of soot into the stratosphere could make temperatures drop by 8 degrees Celsius—3 degrees lower than Ice Age values.
No place on earth will be safe once the nuclear fallout cloud covers the entire earth... There are only places where you will probably survive a couple of months longer then places directly hit..
Maybe an island in the southern ocean off the coast of Antarctica?
If WW3 is a euphemism for full-scale nuclear war between Russia and the US, the southern hemisphere would have the best of chance of riding out a nuclear winter to any degree ... but whether or not civilization would break down nonetheless is hard to say ... doesn't matter much whether there is less radioactive fallout in Patagonia if everyone have been reduced to acting like Neanderthals to survive
and like a volcanic winter, a nuclear winter probably will still lead to crop failures even if people in Patagonia are not directly being irradiated
Any of the small non-relevant countries really because China the United States Russia and Europe will be the four major contenders Australia closely behind because of her ties to Great Britain and generally the safest will be the small Nations like Micronesia or the island of Madagascar or something like that. World War 3 will be fought with nuclear weapons World War IV if there is anyone left alive will be fought with sticks and stones