Will the Roads Be Icy Tomorrow?

Quick answer: roads can ice when the air is 3°C (37°F) or colder, and black ice is most likely when wet roads drop to around 0°C (32°F), usually overnight and before about 9am. Enter your town below to see tonight, tomorrow morning and the next 36 hours, hour by hour.

How it works

What the warnings mean

Severe: snow or sleet, or rain falling at or below freezing (black ice likely).
Hazard: wet roads near 0°C, frost on roads, fog, thunderstorms, heavy rain or strong gusts.
Caution: air at 3°C or below (shaded roads and bridges can still ice), frost possible, or steady rain.
Clear: no weather hazard in the forecast for that hour.

Times are shown in your device's time zone. Forecast data: MET Norway (Norwegian Meteorological Institute, CC BY 4.0), refreshed at most every 30-60 minutes. Place names: GeoNames (CC BY 4.0). This is an air-temperature forecast with simple rules applied, not a measurement of the road surface.

Questions

Icy roads — FAQ

How cold does it have to be for roads to get icy?

Water freezes at 0°C (32°F), but a road surface can fall below freezing while the air is still a few degrees warmer, especially on clear, calm nights. That is why this checker already warns when the forecast air temperature is 3°C (37°F) or lower, and raises the warning when roads are wet and the temperature is close to zero.

What is black ice?

Black ice is a thin, clear layer of ice that lets the dark road show through, so it looks like a wet road. It forms when rain, drizzle, melting snow or dew freezes on the surface. It is hardest to see at night and early in the morning.

Which roads ice first?

Bridges, flyovers and overpasses (cold air reaches them from above and below), shaded stretches under trees or cuttings, high ground, and minor roads that are not gritted or salted. Main roads are usually treated first.

When are icy roads most dangerous?

In the early morning, before the sun has thawed the overnight frost. In Great Britain, police-recorded collisions on icy or snowy roads peak between 8am and 9am, and January has more than any other month.

Is this a road-surface forecast?

No. It reads the air forecast from MET Norway and applies simple, published rules to it. Road surfaces can be colder or warmer than the air. For closures and official warnings, check your road authority (for example National Highways, Traffic Scotland, your state DOT or 511 service) or our live traffic page.