It seems like North Korea has been ready to do a nuclear test for a few months. However, it appears they are waiting for the right moment to justify them conducting the nuclear test to mitigate international condemnation. The fact that the ROK has not unilaterally cancelled the Inter-Korean military agreement despite all the provocations in recent months has denied them one of their justifications for the nuclear test:
Prime Minister Han Duck-soo has said North Korea is ready to conduct a nuclear bomb test, but South Korea and its allies have always been prepared for the North’s major provocation.
“We gather that they are ready,” Han told Britain’s Sky News in an interview, “although we do not know exactly when” a nuclear test would happen.
North Korea has launched a flurry of short- to long-range missile tests so far this year and has widely been expected to carry out what would be its seventh nuclear test.
Han said South Korea and its allies have been on alert over the possibility of North Korea’s nuclear test.
Yonhap
You can read more at the link, the Kim regime will eventually find something to justify their test. The real question is what does the U.S. and the ROK do in response?