Spot on advice this. Exactly what I do.
The TPMS system on these cars only measures and indicates a pressure loss from a defined point. Resetting the TPMS sets this defined point hence the need to accurately measure pressures, inflate as required and then re-measure and then set the TPMS to register this defined point as being exactly what the tyres should have in them.
Pressure does naturally drop in very cold weather so I always try to set mine with cold tyres on a day where the ambient temperature is above about 6 degrees. Equally, natural sunlight on a summer’s day will warm a tyre which will increase it’s pressure. Not uncommon to measure a 2-3 PSI difference from side to side on a hot day, the side exposed to the sun measuring higher. Then when the temperature drops both sides measure the same again. You get the same effect by driving - the constant rolling of the tyre against the road surface and braking and cornering warms up the carcass of the tyre which in turn raises the temperature of the air inside and therefore the pressure. Hence the importance of checking and setting pressures on cold tyres.