Vytautas Sakalauskas of the Lithuanian Hydrometeorological Service forecasts that temperatures will fall to -24C in some areas in the early hours of Friday and then in the early hours of Sunday. Elsewhere in the country, temperatures will range between -15 and -20C.
These will be the coldest nights in Lithuania since early January 2017, when the mercury dipped to -30C in some places.
Other nights of this week will be cold as well, with temperatures at below -10C. The days will be milder, but temperatures will stay below zero.
Similar weather conditions will continue until the end of February, Sakalauskas said.