Yorkshire Ambulance Service is warning people across the county to take extra care after a weather alert for freezing temperatures and ice was issued.
The Met Office has put out a yellow weather warning for ice for the whole of Yorkshire.
The warning applies from 6pm on Wednesday through the night until Thursday.
In parts of the county snow has already fallen, with snowstorms hitting Sheffield earlier on Wednesday, while sleet showers and hail have also made conditions treacherous elsewhere.
If you're driving or commuting tonight or tomorrow, the roads may become dangerous in places due to black ice, while some train services could suffer delays.
The Met Office forecast says: "Following a spell of rain, sleet and snow, temperatures will fall quickly allowing ice to form on untreated surfaces.
"Further showers of rain, sleet and snow will follow in the west on Thursday morning, potentially diluting overnight treatments.
"Some roads and railways are likely to be affected with longer journey times by road, bus and train services. Some injuries from slips and falls on icy surfaces are possible."