Within a week, the Lowcountry will go from flirting with record high temperatures in the 80s to fretting over lows in the 20s.

By the numbers

83° The highest January temperature recorded in Charleston, 1950 (Beaufort holds the state record, 86 on the same day) since 1938.81°Saturday’s high in Charleston, a record for Jan. 12, considered the “normal” high that day for San Juan, Puerto Rico.79° Monday’s high, a record for Jan. 14. 77° to 6°Biggest temperature swing within the month of January, 1985.36°The average degree swing between the highest daily temperatures during January.26°Number of January days reaching 80 degrees or more in Charleston since 1938.0Number of years that there were no winter nights at freezing or below in Charleston.Sources: S.C. Climatology Office, National Weather Service, Charleston

There’s a word for that: January.

Widely swinging temperatures are closer to normal here this time of year than they are to the extreme. In fact, January temperature highs and lows ranging from the 70s to freezing happen routinely.

There’s never been a winter it didn’t freeze at least once since the official Charleston weather record started in 1938, said State Climatologist Hope Mizzell.

More unexpectedly, there’s only been 26 days with temperatures higher than 80, she said.

In fact there’s an average swing of 36 degrees between the highest daily temperatures during the month.

AccuWeather.com and Weather.com, private forecasting companies, are calling for lows in the 30s starting Monday with at least a few nights in the 20s for most of the area.

Though the lows are predicted to be in the 40s again by Jan. 26, AccuWeather.com’s longest range forecasts call for them to drop at least to the 30s by the end of the month and stay there into early February.

The federal Climate Prediction Center’s one month forecast is for above normal temperatures.

Reach Bo Petersen at 937-5744, @bopete on Twitter or Bo Petersen Reporting on Facebook.

This story has been updated to reflect that the January record high for the state is 86 degrees. Also, there has never been a winter it didn’t freeze but there have Januarys that ti didn’t freeze. The Post and Courier regrets the error.