The yield curve compares long-term interest rates (like the 10-year) to short-term ones (like the 2-year). Normally long rates are higher — you demand more to lend for longer.
When short rates rise above long rates, the curve inverts. That has preceded every US recession in modern history, usually by 6–18 months. It signals the market expects the central bank to eventually cut rates as growth weakens.
The nuance most people miss: the danger often shows up when the curve re-steepens after an inversion — that's frequently when the slowdown actually arrives.
You don't need to trade the curve directly. Just knowing whether it's inverted or steepening adds real context to any macro read.