How this calculator works
The NWS publishes an average enclosed-vehicle warming series for ambient temperatures of 72-96°F. This page adds that reported temperature rise to the entered starting ambient temperature and linearly interpolates between ten-minute points. It is an illustration, not a vehicle-specific thermal simulation or a forecast. Solar radiation, shade, weather, vehicle colour and ventilation can change the outcome, so none is assigned an unverified multiplier. Never leave a child or pet in a parked vehicle, even briefly. The output is not a safe waiting time. The result is an estimate for information only and is not medical advice.
Formula
Published rise in °F at 0, 10, 20, 30, 40, 50 and 60 minutes: 0, 19, 29, 34, 38, 41 and 43. Illustrative inside temperature = starting ambient + interpolated rise. A temperature difference of 1°F equals 5/9°C.
Worked example
With 80°F outside, the series gives 109°F after 20 minutes and 123°F after 60 minutes. With 90°F outside, the ten-minute point is 109°F.
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Frequently asked questions
Does cracking a window make a safe interval?
No safe interval is calculated. Vehicle heat can become dangerous quickly, and a model cannot establish safety for a child or animal.
Why is the outdoor range restricted?
The published series is labelled for ambient temperatures of 72-96°F. This tool does not extrapolate it to other conditions.
Can I enter cloud cover or a vehicle colour?
The cited series provides no validated adjustment for those inputs. This version uses the published data without inventing correction factors.