semiatic

Frost / icy road warning (snowflake)

The outside-air sensor reads about 4 °C (39 °F) or colder, so the road may be icy even though the air is above freezing — bridges, shaded stretches and exposed roads freeze first. It warns about the road, not about the car; nothing is wrong.

Yellow / amber

Not defined by regulation: a maker convention

What to do

Drive for ice: leave a much bigger gap and brake, accelerate and steer gently — Hyundai's manual says avoid speeding, rapid acceleration, sudden braking and sharp turns. The sensor measures air near the car, not the road surface, so ice is possible with the light out; Mazda warns the reading can be off after the car has been parked, at low speed or when the temperature changes suddenly.

Makes differ: what this light means on your car, the other colours it may use for the symbol and what the car wants you to do are set by the manufacturer, so your car's owner's manual is the authority.

Symbol
A snowflake
Also called
Snowflake light; Icy road warning light; Ice warning light; Low outside temperature warning
Colour
Yellow / amber
Standard
None — a maker convention, described here from 4 makers: Kia, Hyundai, Volkswagen, Mazda

Where makes differ

Kia's sheet draws an amber snowflake that blinks for 10 seconds and then stays lit below 4 °C, with a chime. Hyundai gives 4 °C, or 40 °F in its US manual. Volkswagen shows a white snowflake beside the temperature display below about +4 °C and keeps it until the air is above +6 °C.

Not defined by regulation: a maker convention

Neither US FMVSS 101 (Tables 1 and 2) nor UN Regulation No. 121 lists this light, so no rule fixes its symbol or its colour. What follows is what the makers cited below say; other makes, and other model years of the same make, may draw it differently.

Neither FMVSS 101 nor UN R121 lists an ice or low-temperature tell-tale.

Other yellow / amber maker lights

Diesel particulate filter (DPF) lightBox full of dots with a pipe at each end · maker conventionAdBlue (DEF) warning lightLiquid container with a wavy fill line and a drop · also red · maker conventionEPCEPC (electronic power control) lightThe letters EPC · maker conventionLane assist (lane keeping) lightLane markings running away from you, dashed line in the middle · also green · maker conventionForward collision warning lightCar seen from behind with radar arcs around it · also red · maker conventionBlind spot monitor lightTwo cars side by side with signal waves between them · maker conventionAdaptive cruise control (ACC) lightSpeedometer dial with a needle · also green · maker conventionAUTOHOLDAuto Hold lightThe words AUTO HOLD · also green · maker conventionPower steering warning light (EPS)Steering wheel, sometimes with an exclamation mark · also red · maker conventionWater in fuel light (diesel)Fuel pump with water drops beside it · maker conventionGearbox (transmission) warning lightCog wheel with an exclamation mark · maker convention?Key not detected lightKey with a question mark · maker conventionBulb failure (exterior light) warningLight bulb with rays and an exclamation mark · maker conventionHill descent control lightCar pointing down a slope · also green, red · maker conventionAAuto stop-start lightLetter A inside a circular arrow · also green · maker conventionService due (spanner) lightA spanner (wrench) · maker conventionLow engine oil level lightOil can above a wavy level line · maker conventionLow washer fluid lightWindscreen with a dashed fountain of spray · maker conventionKey battery low lightKey fob beside a small battery · maker conventionImmobiliser (security) lightCar outline with a key inside it · also red · maker conventionReduced power (tortoise) lightA tortoise · maker conventionPedestrian warning sound off or faultyWalking figure with sound waves · maker convention4WD / AWD warning lightFour wheels joined by axles and a drive shaft · maker convention

All yellow / amber dashboard lights, regulated ones included

Sources

No regulation defines this light, so it is described from 4 carmakers' own manuals or owner pages, each fetched and checked on the date shown:

Written in our own words; the makers' pages cover their own models only.