I wonder if it ever has been
The highest temperature recorded on a January day is 79, in 1950. What day that was will take additional research.
It is possible ... but highly unlikely ... for it to be 70 or 80 degrees in Baltimore, MD on January 20th. Record high of 71° was set in for that day in 1951.
Yes it is possible. We've had some freak years.
Record high for January was 79 degrees set back in 1950