A winter heat wave made history during the weekend, setting dozens upon dozens of records in the eastern United States. As temperatures shot up more than 30 degrees above normal, January seemed to leap ahead to May.

Boston, where highs are normally in the mid-30s at this time of year, soared to 74 degrees Sunday, joining several other cities in posting their warmest January day ever observed.

The abnormally toasty conditions occurred as warm air surged out ahead of a deadly storm system responsible for severe weather in the South on Friday and Saturday. It happened amid a weather pattern that has been more springlike than winterlike since late December.

The magnitude of the warmth was yet another reminder of the influence of climate change, which is intensifying heat events and having a detectable influence on day-to-day weather, according to studies.

Record warmth was widespread

A huge area of the country to the east of the Continental Divide experienced days of springlike readings. Warmth this intense over an area so large is very atypical during what is often the coldest time of the year across the Lower 48 states.

Records began to fall Thursday in the central United States, including in Kansas City, where it was 66 degrees.

The warmth expanded eastward Friday as warm weather records were set from Texas and Florida to southeast Canada.

The January heat wave peaked over the weekend. More than 100 long-period record highs were set or tied Saturday and Sunday alone. Not only did daytime high temperatures soar to unprecedented heights, but scores of overnight low temperatures were also at record-warm levels.

Saturday’s 80 degrees in Charleston, W.Va., was among the more notable high temperatures. It set a record for Jan. 11 and was the second-highest temperature of any day in January for the period from December through February. The city fell short of its highest January temperature by one degree.

Among daily records across two dozen states, many were significantly higher than old ones, like the 67 degrees in Albany, N.Y., on Saturday that sailed by the old mark of 57 degrees from 1945. In Huntington, W.Va., the high of 78 degrees demolished the old record of 66 degrees from 1963. In Springfield, Vt., it reached 62 degrees, compared to the old daily record of 50 degrees from 2017.

Record January warmth in Boston and elsewhere

With thousands of scientists descending upon Boston for the American Meteorological Society’s 100th annual meeting, the conference lived up to its reputation for featuring memorable weather. In this case, the opening of the conference coincided with the warmest January day the city has ever observed.

Beantown hit 74 degrees Sunday, not only the record high for January, but also its second day in a row reaching 70. Back-to-back 70-degree readings in January is unprecedented in the city’s history dating to the 1870s. Talk about winning the weather lottery!

Boston wasn’t alone.

Not far to the southwest, Rhode Island’s capital city of Providence rose to 70 degrees Sunday. That was the first time that city has reached 70 degrees during the month in more than 100 years of records. Bridgeport, Conn., also set a January record high of 69 degrees, while becoming the earliest it’s been that warm in the year. Naples, in deep South Florida, rose to 89 degrees, which surpassed the city’s old monthly record by several degrees.

Other locations, such as Chicopee, Mass., (70 degrees, tied) and Parkersburg, W.Va., (78 degrees, tied) also reached their January high mark, while spots such as Hartford, Conn., saw their second-warmest January day.

Among the records for warmest overnight low temperatures, Savannah, Ga., tied its all-time January record-warm low only falling to 68 degrees (also done in 1937). Raleigh, Key West, and Tallahassee were among others that posted one of their top two warmest low temperatures during the month of January.

The cause

This most recent episode of eastern U.S. warmth was caused by upper-level high pressure that flexed its muscle as a big storm cut through to the west. The combined flow around weather systems pumped springlike air northward.

The pattern pumping mild air up the East Coast dates back to the days before Christmas. Its persistence has helped much of the east see temperatures some 7 to 15 degrees above normal for the start of the month.

It does seem that we’re on the cusp of a pattern change across the Lower 48, which should allow much colder weather to return to the east and, potentially, snow. The flip to a more wintry pattern may commence as soon as Friday this week.