Environment Canada issued a fog advisory at 4:39 a.m. Tuesday, with near-zero visibility either expected or occurring around the southeast, including the Estevan, Weyburn, Carlyle, and Oxbow areas.
The government agency expects the fog to lift later in the morning.
Meanwhile, the province's Highway Hotline says visibility is good on highways around Estevan, Carlyle, and Oxbow as of 6:01 a.m., but reduced near Weyburn and Regina.
You can find the detailed, interactive map of highway conditions here.
The advisory said to expect "areas of very dense fog Monday night into Tuesday morning," though conditions will improve throughout the morning hours once the sun comes up (around 8 a.m.).
"Visibility may be significantly and suddenly reduced to near zero. Travel is expected to be hazardous due to reduced visibility in some locations. If visibility is reduced while driving, slow down, watch for tail lights ahead and be prepared to stop."