This week has a ‘blue’ and ‘super’ moon. Here’s what to know.

Some lunar-related nuisance flooding notwithstanding, for moonlight connoisseurs, this is quite the special week. The moon is making its closest annual approach to Earth, and will reach its instant of fullness over Philly at 9:37 p.m. Wednesday.

Its proximity makes it a “super” moon in what has been a harvest season for those things. And since it is the second of the month, it is knighted a “blue” moon. Savor it: You won’t have a chance to see a super-blue moon again until 2037.

Here are a few things to know, including the fact that while the term has a questionable history, yes, the moon really has turned blue on several occasions.

But not this week.

» READ MORE: Space tourism is taking off. You probably can't afford it.

Blame the moon for the nuisance flooding expected this week at the Shore and along the Delaware River. The moon is a grand mover of the tides, those “long-period waves that roll around the planet,” in NOAA’s words. The moon’s influence ebbs and flows depending on its distance from Earth, and it’s making its closest encounter of the year.

During its elliptical orbit in a 29.5-day cycle, the moon’s distance from us typically ranges from 226,000 to 253,000 miles. On Wednesday night, however, it will come extra close, within 222,000 miles.

The moon doesn’t act alone: The gravitational might of the sun also has an effect on tides, and during full and new moons the earth, sun, and moon are aligned directly. But our natural satellite’s proximity makes its influence twice as strong as the sun’s.

Another major factor in tide levels is water temperature. Warmer waters take up more room. Thus full-moon high tides at perigee, when the moon is closest to Earth, can be 10 to 15% higher in summer than in winter, according to NOAA data.

» READ MORE: NOAA sees more nuisance flooding for the region

Just what all this would mean for Florida’s west coast on Wednesday would depend on when in the tidal cycle Hurricane Idalia approaches land.

This “super” moon — using the definition of the moon’s perigee coinciding with the full moon — is the third in a quartet that began in July. We’ll get another one in September. How unusual is it to get four in a row? Evidently, not very. It will happen against next year.

What is different about this sequence is that the four are occurring within three months. That’s because this one is a so-called blue moon, which has come to mean the second full moon in a month. The first was on Aug. 1.

How the term took on its current meaning remains somewhat of a mystery. NASA says the label dates to the 1500s, when it was used to designate the third of four full moons in a season.

Philip Hiscock, a folklorist with Canada’s Memorial University, searched long and hard to find out how it came to mean what it does today. In a 2012 article in Sky & Telescope, he said that the popular definition appeared in the magazine in the 1940s but that the writer was incorrectly describing a reference from an old almanac. The new meaning took on a life of its own, he said, and even appeared as a Trivial Pursuit question. The rest is history, or at least distorted folklore.

It has been a while, but the moon has appeared blue on several occasions.

After the cataclysmic eruption of Krakatoa in 1883, ash plumes that were filled with particles that scattered red light transformed the volcano’s clouds into blue filters. Full moons, quarter moons, crescent moons, in-between moons all appeared blue for years, according to NASA, with sightings reported all over the world.

A hundred years later, blue moons developed after the eruption of the El Chichón volcano in Mexico, and reportedly were visible after the eruptions of Mount St. Helens in 1980 and Mount Pinatubo in 1991. And in 1953, a massive forest fire in Alberta, Canada, created blue moons all the way to England.

The moon will look oversized and spectacular rising in the southeast Wednesday at 7:30 p.m., and will outshine every star.

Although physically it will be 14% closer than a full moon at apogee — when the moon is at its furthest point from Earth — it will look 30% brighter, said Karen Masters, professor of astronomy and physics at Haverford College. No need to rub your glasses, she said: That’s the result of “the same physics that makes headlights of nearby cars look so much brighter than distant ones.”

» READ MORE: Have trouble sleeping this week, this article may explain why

If you miss it this time around, you’ll get another shot at a super blue moon in January 2037, and another two months later. The Phillies’ Bryce Harper will be 44, and it’s possible you’ll be older, too.

The sky conditions, unfortunately, aren’t looking great for Wednesday night, but the prospects are considerably better Thursday and Friday nights. The moon is 100% full for roughly a nanosecond. On Thursday, it still will be at 99% fullness, and 95% on Friday.

Masters said that a “personal favorite” of hers is the “morning moon.” It won’t be setting until 6:53 a.m. Thursday, and 8:11 a.m. Friday. It will be visible after sunrise for a week to 10 days.

“The moon is always beautiful,” she said.