If you mean safe in terms of residual radiation due to the atomic bombings of 1945, the answer is yes. It has been safe enough to visit for more than 71 years: “About 80% of the total amount of residual radiation was released within 24 hours of the bombing. read more
It is now safe to visit both Hiroshima and Nagasaki. The people suffering from cancer where exposed to the radiation in 1945 but the radiation levels are now back to normal and both cities are beautiful cities to visit. read more
The best time to visit Japan for the best Hiroshima and Nagasaki weather is from April to September. It depends on what else you want to do. read more