UPDATE: The Met Office has stepped down the warning for Cornwall and localised to Gloucestershire.
Sleet is said to be settling on Chiverton Cross as of 8.25pm.
A spokesman said: "Initially Cornwall, Gloucestershire, Wiltshire and Devon had been forecast snow, but it has since been forecast that Gloucestershire will be the only area to see snowfall.
EARLIER: Snow has been forecast to fall in Cornwall tonight and into Wednesday morning.
The Met Office, the Exeter-based national weather forecast company, has issued a public warning about snowfall and urged people to “be aware”.
The warning will remain in place until 10am on Wednesday morning.
The snow will accompany gale force winds after heavy rain showers, it is forecast.
A spokesperson from the Met Office said: “Showers will turn increasingly to snow. On low ground, lying snow will tend to melt between showers by day but 1-3 cm may settle on Tuesday evening and night.
“Icy stretches will also form in the evening, these lasting well into Wednesday morning in the north.
“The public should be aware of the risk of some travel disruption and difficult driving conditions. This is an update to the warning issued yesterday, to include more of Wales and central England.”