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Lower temperatures expected this week might make weather nicer for bicyclists at the Pickett Bridge Recreation Area in Mount Pleasant. Gavin McIntyre/Staff

Temperatures could plunge into the 50s overnight Thursday into Friday — a weather shift so startling that meteorologists have a name for it: normal.

The night may be the lowest point of a 10-degree-or-so drop in temperatures in the Charleston area expected to start Wednesday.

Highs that have been in the 90s will be in the low-80s. Humidity that had spiked as high as 99 percent last week was already dropping sharply on Tuesday as the drier weather began moving in.

The culprit is a push of weather from the north that National Weather Service forecasters called a "backdoor cold front."

So, it's fall?

Well, if you want.

"Just looking at the weekend, the high is going to be back up to 85," said Weather Service meteorologist Rebecca Davidson.

"Still, 85 is better than 95," she said. "Hopefully, we're out of the 90s and we'll start to cool down."

Temperatures around Charleston have been as much as 6 degrees higher than normal, according to the S.C. Climate Office. The highs and lows have been more similar to Orlando, Fla., than the Lowcountry.

The June-August average temperature statewide ranked the 22nd warmest on record, said State Climatologist Hope Mizzell.

"That's not a record. But it's still above normal," she said.

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Reach Bo Petersen at @bopete on Twitter or 843-937-5744.