Resolves YES if North Korea tests a nuclear weapon before the end of the year. NO otherwise.

https://en.wikipedia.org/wiki/List_of_nuclear_weapons_tests_of_North_Korea

 and reliable media reporting for resolution. I will use local time in Korea.

North Korea has done 6 nuclear tests, the first in 2006 and the most recent in 2017. In recent weeks, they've conducted a large number of (non-nuclear) missile tests. Satellite imagery also indicates preparations for more underground nuclear tests are underway: 

https://time.com/6219676/north-korea-nuclear-missile-biden/

https://beyondparallel.csis.org/punggye-ri-update-continued-activity-near-tunnel-no-4/?_thumbnail_id=6041

all preparations for a nuclear test appeared completed at Tunnel No. 3

both the United States and South Korea assess North Korea as having finished all preparations for conducting a nuclear test using this tunnel.

The timing of a seventh nuclear test now remains solely within the hands of Kim Jong-un.

https://manifold.markets/post/nuclear-risk-forecasting

 for a dashboard of other nuclear risk questions along with commentary and analysis.

Update: In case it matters, the timezone I'm using will be local time in Korea.