The Department of Infrastructure says the Mountain Road is unlikely to open this weekend.
On Facebook, it says more freezing weather looks set to bring further wintry showers along the route.
It closed the length of the road earlier today after heavy snow overnight.
The DOI says it'll continue monitoring conditions and will reopen it sooner if it's safe to do so - but adds it's likely to open again on Monday, February 16.
Still time for seasonal flu jabs, says Manx Care
Firefighters tackle three incidents in one afternoon
List of buses running during today's strike action
Hospital bed occupancy falls
More driver services to go online
How many people come here without visas?
Temporary traffic lights on TT course
Weather warning for icy patches