Monday will be somewhat warm still at +11..+16 degrees. At night to Tuesday the air will cool down to +1..+6 degrees, and in a few regions of Latgale and Vidzeme it'll stay at 0..-3.
Tuesday will be sunny but significantly colder at +7..+12 degrees.
It'll be mostly dry and cold the next week. During the second half of the week, though, some clouds will shop up and precipitation (rain or snow) is possible on a few days.
The nights will be freezing be about -4..+1 degrees in most of the country and +2..+6 degrees in the coastal regions. Some nights the temperature will lower to -5..-7.
The coldest nights will be those to Thursday and Friday. During the day the temperature will rise to +4..+9 degrees and +10..+11 at some of the coastal regions.