Thick fog has started to settle over parts of the region, prompting Environment Canada to issue a special weather statement.
The weather agency issued the alert shortly after 7 p.m. Tuesday as dense patches of fog is expected in areas including London, Parkhill and Eastern Middlesex County, Oxford County, Perth County, and Southern Grey County.
"Visibility may be significantly and suddenly reduced to near zero. If travelling, be prepared for areas of near-zero visibility," a statement from Environment Canada read.
Those venturing out Tuesday evening and overnight are advised to turn their lights on while driving and maintain a safe following distance.
The fog is expected to lift by Wednesday morning.