The previous record for January was 1.9 degrees, set in 1989, Donatas Valiukas of the Lithuanian Hydrometeorological Service said in a press release.
"The coldest January on record in Lithuania was in 1987, when the average temperature for the month was minus 15.1 degrees," he added.
Vilnius also had its warmest January since weather records began in 1778, with the average temperature in the capital at 1.9 degrees last month.
January 2020 was also exceptional in that Lithuania did not have a single day with snow cover, Valiukas noted.
As a result of global climate change, the average January temperature in Lithuania has risen by 2.9 degrees since 1961.