Police Scotland said people should delay their journeys if possible.
Ch Supt Scott McCarren, head of road policing, said: “Stopping distances can be at least double on wet roads compared to dry conditions, and spray can reduce driver visibility.
“HGV and bus drivers should drive with extreme caution and be aware you may be asked to park at a suitable position by the police.”
He added: “If you need to travel, please drive to the conditions and take extra time for your journey.”
ScotRail has asked passengers to check its social media and journey check website , externalfor updates.
West coast ferry operator CalMac has already warned of disruption to its sailings, and Highlands and Islands Airports Ltd (Hial), said the adverse weather could impact on flights.