This is different from Jupiter's closest approach to Earth, which occurs on May 10. While you'd think Jupiter would be closest to Earth when it's in opposition, that's not the case due to each planet's slightly elliptical orbit. Here's how EarthSky explains it:
"The reason is that the orbits of Earth and Jupiter aren’t perfect circles, and, moreover, their orbits aren’t exactly on the same exact plane," per the report. "They’re both very nearly circular, and go around the sun on almost the same plane, but not quite. Jupiter’s distance from the sun varies by only about 10.1% between perihelion (closest point to sun) and aphelion (most distant point from sun)."
If both Earth's and Jupiter's orbits were perfect circles, Jupiter's closest approach to Earth would fall on the same day as its opposition. But, alas, even space isn't perfect.