The hazardous rain zone can easily extend 10 to 20 miles (15 to 30 kilometers) from detonation, depending on explosive performance and weather conditions. Heat is a problem for those closest to the explosion. Minor first-degree burns can occur up to 11 km (6.8 miles) away, and third-degree burns, which destroy and blister skin tissue, can affect anyone up to 8 km (5 miles) away. Third-degree burns that cover more than 24 percent of the body would likely be fatal if people don't get immediate medical attention.
Nuclear explosions also produce clouds of dust and sand-like radioactive particles that disperse into the atmosphere, known as nuclear rain. If you somehow survive all of that, you still have to deal with radiation poisoning and nuclear consequences. Essentially, I would like to avoid countries with access to nuclear weapons and those involved in nuclear agreements. However, for more information on the current state of nuclear weapons in the world, including the scale of bombs, you can visit the Nuclear Notebook in the Bulletin of Atomic Scientists.