What weather temperature does a car perform best?

Answer 1

A car, an airplane, a ship, or anything else properly manufactured will work best at a temperature of 15°C and an atmospheric pressure of 1013 hPa. That is because it is the average temperature and pressure on earth and called the Standard Atmosphere (SA). All manufacturers of engines, etc. take that as a reference to produce their products. Carburettor tuning, oil viscosity, aircraft instruments, etc. are aimed at that standard.

Answer 2

Always after warming up when the temp on the gage reads normal.

Note:

Cold temp keeps the engine from over heating, but it can crystallize the Mattel the the shat on the Axel can beak (very cold Siberian type temp).

Real hot whether will over heat the engine and you can loose coolant causing the engine to overheat and fail.

Axel grease can beak down and bearings and Axel can fail.