Tuesday night saw the thermometer drop to -24C (-11F) in Daugavpils with central Riga at -15C and coastal areas of Kurzeme considerably milder at around -8C.
Wednesday and Thursday nights could see temperatures drop to around -28C, LTV weatherman Toms Bricis said.
However, the arrival of a new weather system from the west should see daytime temperatures return to somewhere around freezing temperature for the weekend.
Wind speeds may also pick up as a result, and more snow is expected early next week.