Road Mirage Simulator (2D)

Road Surface

Asphalt temperature 55°C

Ambient Air

Ambient air temperature 25°C

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Live Readout

Apparent mirage distance

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True object distance

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Air temperature at ground level

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How it works

Hot asphalt heats the thin layer of air touching it. Warm air is less dense, so its refractive index n is slightly lower than the cooler air above — and n keeps rising with height as the temperature falls off. A ray of light from the sky (or a distant car) grazing toward the road at a shallow angle curves smoothly back upward inside that gradient instead of hitting the ground, the same way it would reflect off real water.

The eye can't tell the ray bent — it extends the incoming direction backward and "sees" an inverted image projected onto the road surface, right where the ray last touched bottom. That is the shimmering "puddle." It is always sky or distant-object light, never water, which is why it recedes forever as you drive toward it: the turning point simply moves with you.

Raise the asphalt temperature and the near-ground gradient steepens, so shallower rays turn back sooner — the apparent puddle creeps closer. Raise the ambient temperature instead and the whole gradient weakens, since there's less contrast between the hot road and the air above it, and the mirage can vanish entirely.