But what does it all mean?
Perihelion is that point in a planet's orbit where it, the planet, is nearest the sun. For the outer planets, this also brings them nearer the Earth.
Opposition is when an object, as viewed from the Earth, is opposite the sun in the sky; i.e. it rises at sunset and is overhead, or on your celestial meridian at midnight. The outer planets are always best viewed at opposition. If they're at opposition and perihelion at the same time it's downright sinful. For Mars, this occurs once every fifteen years; this year, right now, during late August, these two events take place within two days of each other. And it's as good as it's been in more than, yes, 50,000 years!
Mars reaches perihelion on August 30, just two days after opposition. It will be a mere 0.373 astronomical units (a.u.) from us, or 55,760,000 km. And it will be a polished fiery gemstone, shining at a gaudy -2.9 in magnitude.
Mars orbits the sun at a mean distance of 1.52 a.u. (The mean distance of our orbit is 1 a.u.) Moving about 20% slower as it orbits the sun than does the Earth, it takes 1.88 years to complete one orbit. From our point of view, at a cozy 1 a.u. from the sun, it takes us 2.13 years to catch up with Mars. In other words, it'll be at opposition again 2.13 years from now. It will not, however be at perihelion. Mars will have been at perihelion about three months earlier.
If there is anything negative in the shiny Mars apparition it's that it takes place in Aquarius, which is a bit more southerly than northern observers would like. Southern hemisphere observers, though, have a front seat.
Unlike here on Earth, where our perihelion has little effect on our climate, Mars' seasons are profoundly effected. Because of its widely varying distance from the sun from aphelion (furthest from the sun) to perihelion, the red planet will receive 45% more sunlight. Its southern hemisphere, now tilted toward the sun, will have summer. Its southern ice cap will shrink, or disappear altogether. Unless one of those relentless Martian dust storms kicks up, this should be obvious in even modest telescopes, as long as the sky is steady.
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