It's going to get foggy in many areas of Metro Vancouver and across the western Fraser Valley tonight (January 22) and on Sunday (January 23) until midday.
That could lead to some tricky driving conditions.
"Visibility may be significantly and suddenly reduced to near zero," Environment Canada said in a statement. "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."
Fog is often thought of as a low-lying cloud and it's the result of the condensation of water vapour into droplets that hang in the air.