The Watch Score is NOT a probability of impact. It's a single number to help you sort a busy feed — a weighted blend of four factors.
Estimated diameter range — bigger objects carry more interest.
How near the miss distance is, on a log scale against the Moon's orbit.
Speed at approach (v∞), which scales kinetic energy.
How soon the approach is. Distant future passes score lower.
Data: NASA/JPL CNEOS · ESA NEOCC · IAU MPC.