Up to 20cm (8ins) of snow is expected in parts of Hampshire and the Isle of Wight over the weekend.
The Met office said significant snowfall is expected early on Saturday although coastal areas are expected to escape the worst of the weather.
Hampshire Constabulary advised partygoers to dress appropriately because of freezing temperatures and icy winds.
Christmas shoppers are also being warned not to drive unless necessary.
Police said anyone needing to drive should stick to main roads which are on the priority gritting routes and be fully prepared with warm clothes, a hot drink, a shovel and a fully-charged mobile phone.
Hampshire Constabulary's 4x4 vehicles are on standby to help if needed.
South West Trains said it would be operating a revised service on Saturday. The latest timetables are available on the company's website.
Southampton Airport said it had no snow so far. The airport, which operates about 100 flights a day, said it had to cancel eight flights - four arrivals and four departures, because of the weather.
Passengers are being advised to check with the airline before setting off for the airport.
Between five and 10cm of snow has been predicted in most areas, with up to 20cm in rural areas.